Can Kouran make other characters unbreakable?

[danatoth689]

Can the shrine join Kouran and the black guard? I didn't think it could because it is not Unbreakable.

MOD'S EDIT:
split from The End Times are here! (battle preparation)
Calisson

[Haagrum]

Can the shrine join Kouran and the black guard? I didn't think it could because it is not Unbreakable.

It wouldn't be able to join the unit during the game. However, if it starts in the unit (bearing in mind that the Shrine is deployed before characters), it can remain in the unit after Kouran joins and makes the unit Unbreakable.

[Calisson]

Can the shrine join Kouran and the black guard? I didn't think it could because it is not Unbreakable.

It wouldn't be able to join the unit during the game. However, if it starts in the unit (bearing in mind that the Shrine is deployed before characters), it can remain in the unit after Kouran joins and makes the unit Unbreakable.

Kouran rule tells that if Kouran is in a BG unit, himself and all models of the unit become unbreakable.
But if Kouran joins a mixed unit like a unit made of BG + shrine, that rule is not in effect since it is not a BG unit.

Summary:
- if Kouran is first to join a BG unit, they all become unbreakable and cannot be joined by anyone or anything else (see BRB p.78).
- if Kouran joins a mixed unit made of BG and anyone or anything else, nobody becomes unbreakable until Kouran remains the only remaining non BG.

[Dalamar]

The unit is still a BG unit. Shrine joins units like characters do, and characters joining units don't suddenly change what the units are.

Specific order is important. Once Kouran is in the unit, all models in it become unbreakable and as such can't be joined by anyone else. But you could put a dozen characters in a unit of BG and then add Kouran to it, making everyone unbreakable.

[Calisson]

The unit is still a BG unit. Shrine joins units like characters do, and characters joining units don't suddenly change what the units are.

Specific order is important. Once Kouran is in the unit of BG, all models in it become unbreakable and as such can't be joined by anyone else. But you could put a dozen characters in a unit of BG and then add Kouran to it, making everyone unbreakable.

I beg to disagree with what is in red and have to correct you in yellow.

-=-=-

The ambiguity comes from using the same word, "unit", for several things (see BRB p.99).
In your example of 20 BG + 12 characters + Kouran, the word "unit" describes:
- 20 BG + 12 characters + Kouran, i.e. the combined unit, but also:
- 20 BG + 12 characters, i.e. the initial unit as opposed to Kouran joining it.
In the "unit" made of 20 BG + 12 characters, the word "unit" describes the combined unit, but also:
- 20 BG + 11 characters.
In that last unit, the word "unit" describes also:
- 20 BG + 10 characters, etc.
- 20 BG + 9 characters
...
- 20 BG + 1 character
or
- 20 BG.

All of these are referred as "unit".

-=-=-

Character joining units actually do suddenly change something: the previous unit is now a part of the newly formed combined unit.
20 BG are a unit of BG; they make together a unit of infantry.
20 BG + 1 shrine are not a unit of BG: they are a combined unit. They are not either a unit of infantry, for the record: proof is p.99, "Movement", which indicates that in the combined unit, individual models retain their respective troop type.

-=-=-

With these clarifications, I can only consider that as soon as a unit of BG is joined by anything, the combined unit cannot be considered to be a unit of BG; only the BG part is a unit of BG.

- If Kouran joins 20 BG with no other character, the 21 become unbreakable and can no longer be joined by anything.
- If Kouran joins 20 BG + 12 characters, Kouran has not joined a unit of BG; Kouran's rule is not triggered and the 33 models are not unbreakable.

[Fastcarfreak]

The unit is still a BG unit. Shrine joins units like characters do, and characters joining units don't suddenly change what the units are.

Specific order is important. Once Kouran is in the unit of BG, all models in it become unbreakable and as such can't be joined by anyone else. But you could put a dozen characters in a unit of BG and then add Kouran to it, making everyone unbreakable.

I beg to disagree with what is in red and have to correct you in yellow.

-=-=-

The ambiguity comes from using the same word, "unit", for several things (see BRB p.99).
In your example of 20 BG + 12 characters + Kouran, the word "unit" describes:
- 20 BG + 12 characters + Kouran, i.e. the combined unit, but also:
- 20 BG + 12 characters, i.e. the initial unit as opposed to Kouran joining it.
In the "unit" made of 20 BG + 12 characters, the word "unit" describes the combined unit, but also:
- 20 BG + 11 characters.
In that last unit, the word "unit" describes also:
- 20 BG + 10 characters, etc.
- 20 BG + 9 characters
...
- 20 BG + 1 character
or
- 20 BG.

All of these are referred as "unit".

-=-=-

Character joining units actually do suddenly change something: the previous unit is now a part of the newly formed combined unit.
20 BG are a unit of BG; they make together a unit of infantry.
20 BG + 1 shrine are not a unit of BG: they are a combined unit. They are not either a unit of infantry, for the record: proof is p.99, "Movement", which indicates that in the combined unit, individual models retain their respective troop type.

-=-=-

With these clarifications, I can only consider that as soon as a unit of BG is joined by anything, the combined unit cannot be considered to be a unit of BG; only the BG part is a unit of BG.

- If Kouran joins 20 BG with no other character, the 21 become unbreakable and can no longer be joined by anything.
- If Kouran joins 20 BG + 12 characters, Kouran has not joined a unit of BG; Kouran's rule is not triggered and the 33 models are not unbreakable.

I disagree. By your own assessment, once Kouran joins the unit of black guard, the combined unit is no longer a unit of blackguard... I think you are taking this rules lawyering too far and interpreting things in your own mind. The base unit being blackguard, are still a blackguard unit, regardless of which characters join the unit...unless otherwise specified by the army book.

[Calisson]

I disagree. By your own assessment, once Kouran joins the unit of black guard, the combined unit is no longer a unit of blackguard... I think you are taking this rules lawyering too far and interpreting things in your own mind. The base unit being blackguard, are still a blackguard unit, regardless of which characters join the unit...unless otherwise specified by the army book.

What do your read in Kouran's rules exactly?
Translated from the French: "If Kouran is in a unit of BG, himself and all models of the unit have the rule unbreakable".

Let's go back to Dalamar's 20 BG + 12 characters + Kouran
You say 20 BG = "base unit". You say that in Kouran's rule, it is the base unit which is to be considered.
Let's give a try and replace, in Kouran's rule, "unit" by "base unit".

"If Kouran is in a "base unit" of BG, himself and all models of the "base unit" have the rule unbreakable".
With your own interpretation, the 12 characters are not part of the base unit. Therefore, the 12 models are not unbreakable.
Now read BRB p.78, as not all models are unbreakable, then the whole unit is not unbreakable.
In your interpretation, the combined unit is not unbreakable either.


The only way to have unbreakable characters else than Kouran is to consider that, in the sentence "If Kouran is in a unit of BG, himself and all models of the unit have the rule unbreakable", the first "unit" is the base unit of 20 BG and the second "unit" is the combined unit of 32 models including 20 BG.
How in the world can you seriously argue that a single unit, mentioned twice in the same sentence, would sometimes comprise 20 models and sometimes 32 models?

[Haagrum]

There is no concept of a "base unit" in Warhammer's rules.

A character which joins a unit (and, by inference, a model which joins a unit like a character due to some special rule, such as Will of the Gods) is part of the same combined unit (BRB, p99). If that unit is a unit of Black Guard, it does not stop being a unit of Black Guard simply because they have legally been joined by one or more additional models. This claim begs the question, "what would the unit then become?" How would you know what rules and statistics applied to the unit, if adding a character to it changed what that unit was? I'm taking this to an absurd extreme, true - but if a unit of Black Guard stops being a unit of Black Guard as soon as any character joins it, these are reasonable questions to ask, particularly if the rules of the game do not support such a position.

Kouran's "The Right Hand Of Darkness" rule (in the English army book) states "If Kouran Darkhand is in a unit of Black Guard, he and all models in that unit have the Unbreakable special rule."

Nowhere does this rule suggest that every model in the unit has to be a Black Guard model. In fact, the use of "Black Guard" in the first clause, and the words "all models in that unit" without any reference to Black Guard in the second clause, suggests that any model which can legally join a unit of Black Guard will become Unbreakable if Kouran is in the same unit.

Since the Shrine is a model which can legally join the Black Guard unit, before Kouran is placed, it does not prevent the unit from becoming Unbreakable due to The Right Hand Of Darkness. The Shrine could not legally join the unit after it becomes Unbreakable, due to the restriction imposed by the Unbreakable rule.

[Fastcarfreak]

This is exactly as I interpret. ^

[Calisson]

Haagrum, no offence meant, but here is where you use one word for two different things, which leads to your different conclusion.

A character which joins a unit (...) is part of the same combined unit (BRB, p99).

What BRB p.99 says is that "both he and the unit are treated as a single, combined unit".
Contrary to you, BRB never says that the combined unit is the same as the initial unit.

And, as a matter of fact, the combined unit has not the same troop type as the initial unit: read p.99, MOVEMENT.

Nowhere does this rule suggest that every model in the unit has to be a Black Guard model.

Well, couldn't possibly the words "a unit of Black Guard" suggest precisely that?

[Dalamar]

Then why does the rule say "himself and all the models"
Instead of "himself and his unit"
Or, "himself and all the black guard models in the unit"

By including "and every model" the rule opens up to anything and everything in the unit of black guard.

[Red...]

I think this is a good example of evidence that D.Net folk are very good at working through the intricate details of the rules.

To me, it seems that there is a consensus emerging from the discussions: the rules are not clear and so RAI must occur (as RAW is ambiguous). I can see the merits in both arguments, so that seems the best way to play it. And folks running 12 characters in a unit of 20 blackguard should be chased out of the gaming club anyway

[Haagrum]

Haagrum, no offence meant, but here is where you use one word for two different things, which leads to your different conclusion.

A character which joins a unit (...) is part of the same combined unit (BRB, p99).

What BRB p.99 says is that "both he and the unit are treated as a single, combined unit".
Contrary to you, BRB never says that the combined unit is the same as the initial unit.

And, as a matter of fact, the combined unit has not the same troop type as the initial unit: read p.99, MOVEMENT.

Points fairly made, Calisson. For clarity, the part of my post that you've highlighted was to state that the combined unit was one unit, and not to suggest anything else.

As for the underlined text - it never says that the unit is not the same as the initial unit, in terms of characterising it (no pun intended). Without wanting to sound facetious, if you can point me to the part of the rules which tells me how the "new" unit is identified and why the unit in Dalamar's army would no longer be a unit of Black Guard, I'll happily concede this argument.

Nowhere does this rule suggest that every model in the unit has to be a Black Guard model.

Well, couldn't possibly the words "a unit of Black Guard" suggest precisely that?

Only if there was some basis in the rules to conclude that a unit changes its nature or name entirely if you add a character model to it. We have argued over what constitutes a unit of Black Guard, but there is no basis in the rules to conclude that a unit of Black Guard joined by one or more characters (or even a Bloodwrack Shrine, which joins and leaves units like a character) somehow stops being a unit of Black Guard.

As I and others have observed, the words "and all models in that unit" in The Right Hand Of Darkness rule includes no proviso or other restriction. If Kouran was intended to be the only model who could join the unit for this rule to take effect, this could have been clearly stated, or some other restriction imposed on characters joining that unit. The rule does not do this. Compare that, for example, with items and rules which specifically require that no other characters may join the relevant unit (the Pendant of Slaanesh) or that all models in the unit must have a specific attribute (for example, the permanent-Frenzy magic banner in the WOC book which requires all members of that unit to have the Mark of Khorne).

I'll agree to disagree, if that's all we can decide on.

[Calisson]

Thanks for the calm discussion.

Then why does the rule say "himself and all the models"
Instead of "himself and his unit"
=> probably because it would not make sense. Assuming he is in the unit (not my interpretation), then "himself and his unit" is redundant. More likely, the unit is not "his" unit.

Or, "himself and all the black guard models in the unit"
=> Redundant. At the beginning of the sentence, the unit, which is the same unit, was labaled a a unit of BG.

By including "and every model" the rule opens up to anything and everything in the unit of black guard.

Without wanting to sound facetious, if you can point me to the part of the rules which tells me how the "new" unit is identified and why the unit in Dalamar's army would no longer be a unit of Black Guard, I'll happily concede this argument.
=> BRB p.99
Identification: It is a "combined unit".
Troop type: use the rules of the slowest.
Movement: use slowest M.

Nowhere does this rule suggest that every model in the unit has to be a Black Guard model.

Well, couldn't possibly the words "a unit of Black Guard" suggest precisely that?

Only if there was some basis in the rules to conclude that a unit changes its nature or name entirely if you add a character model to it. We have argued over what constitutes a unit of Black Guard, but there is no basis in the rules to conclude that a unit of Black Guard joined by one or more characters (or even a Bloodwrack Shrine, which joins and leaves units like a character) somehow stops being a unit of Black Guard.
=> When 20 BG are joined by 12 characters, I agree that the 20 BG do not stop being a unit of BG.
However, the combined unit
- is treated as a single, combined unit
- has not the same characteristics than BG, as it has to take into account the character's troop type and movement restrictions.

As I and others have observed, the words "and all models in that unit" in The Right Hand Of Darkness rule includes no proviso or other restriction. If Kouran was intended to be the only model who could join the unit for this rule to take effect, this could have been clearly stated, or some other restriction imposed on characters joining that unit. The rule does not do this. Compare that, for example, with items and rules which specifically require that no other characters may join the relevant unit (the Pendant of Slaanesh) or that all models in the unit must have a specific attribute (for example, the permanent-Frenzy magic banner in the WOC book which requires all members of that unit to have the Mark of Khorne).
=> so what?

I'll agree to disagree, if that's all we can decide on.
I'd rather try once more to be convincing

-=-=-

Gentlemen,
You are confusing unit, as an army book entry, and unit as a combined unit. Both are units, but they are not "same".
When 20 BG are joined by 12 characters, it does not change the nature of the 20 BG inside the combined unit, I agree.
But you go much further and pretend that the 36 models have the same nature than the initial 20?
What kind of logics do you use?
Please prove your point!

[Haagrum]

Thanks for the calm discussion.

<snip> NOTE: The point about "combined units" was cut here so it could be addressed below.

As I and others have observed, the words "and all models in that unit" in The Right Hand Of Darkness rule includes no proviso or other restriction. If Kouran was intended to be the only model who could join the unit for this rule to take effect, this could have been clearly stated, or some other restriction imposed on characters joining that unit. The rule does not do this. Compare that, for example, with items and rules which specifically require that no other characters may join the relevant unit (the Pendant of Slaanesh) or that all models in the unit must have a specific attribute (for example, the permanent-Frenzy magic banner in the WOC book which requires all members of that unit to have the Mark of Khorne).
=> so what?

It demonstrates that if the intention was to prevent The Right Hand of Darkness from making the unit Unbreakable if there were other characters joined with it, on the basis that they were not "Black Guard", this should have been explicit in Kouran's rules. GW has done precisely that in other cases. They have not done it here.

There are two obvious explanations. Either it's an omission in error (a contention apparently based on speculation about the author's intentions), or it has been left out intentionally because other characters are not prohibited from joining that unit, (which is the inference I've drawn, on the basis that other rules do impose such a restriction and this one does not).

Simply saying "so what?" does nothing to advance the claim that a unit of Black Guard joined by characters and/or models which join units like characters stops being "a unit of Black Guard".

Gentlemen,
You are confusing unit, as an army book entry, and unit as a combined unit. Both are units, but they are not "same".
When 20 BG are joined by 12 characters, it does not change the nature of the 20 BG inside the combined unit, I agree.
But you go much further and pretend that the 36 models have the same nature than the initial 20?
What kind of logics do you use?
Please prove your point!

Calisson, you are also making an assumption - that a "combined unit" is different from a "unit". A unit with characters and a unit without characters are both still "units". A unit of Black Guard is still a unit of Black Guard, regardless of how many characters join it. All of the models in that unit, including any characters, are treated "as a single combined unit for all rules purposes" other than in respect of the exceptions laid out at BRB p99.

There is no separate game concept of a "combined unit", other than to explain what happens when one or more characters (each of which forms a unit by itself) joins another unit. It simply means that you no longer treat the character(s) and the unit separately for rules purposes, except as specifically provided. Otherwise, you could just snipe out characters with Fireballs. That is as far as the concept of "combined unit" goes, because it's as far as it needs to go.

[Calisson]

if the intention was to prevent The Right Hand of Darkness from making the unit Unbreakable if characters joined it, on the basis that they were not "Black Guard", this should have been explicit in Kouran's rules. GW has done precisely that in other cases. They have not done it here.
=> Sure they did! Earlier in the very same sentence, they specified, explicitely, that it was "a unit of BG".

(...)

Calisson, you are also making an assumption - that a "combined unit" is different from a "unit". => It is not an assumption, it is the rule.
"Units" are defined p.5 & p.134. "Combined units" are defined p.99. Different rules for different concepts.

A unit with characters and a unit without characters are both still "units". => Fully concur.
A unit of Black Guard is still a unit of Black Guard, regardless of how many characters join it. => you make the confusion, once more.
I agree that the 20 BG inside the combined unit of 34 are still a unit of 20 BG.
However, we are talking about the 34 models, and considered together, they are not a unit of BG, please! A unit of BG, that's a unit made of models from the BG entry in the army book.

There is no separate game concept of a "combined unit", other than to explain what happens when one or more characters (each of which forms a unit by itself) joins another unit. It simply means that you no longer treat the character(s) and the unit separately for rules purposes, except as specifically provided. Otherwise, you could just snipe out characters with Fireballs. That is as far as the concept of "combined unit" goes, because it's as far as it needs to go.
=> agree, they are no longer treated separately.
However, contrary to what you seem to believe, there is no rule to tell that the combined unit is the same as any of its component.
Worse for your argument, there are rules which prove the contrary: see combined units, movement, p.99.

In the discussion, Kouran does not join a unit of 20 BG, he joins a combined unit of 20 BG and 12 characters.
It really puzzles me to understand how in the world you could argue that 20 BG joined by 12 characters are, combined together, a unit of BG.

[Haagrum]

Calisson, ultimately our disagreement comes down to whether a unit plus characters can still be considered to be that unit. Don't read into the semantics of that statement - I'm just describing what I see as the disputed point.

At the risk of over-simplifying: you can't describe the unit in question accurately, with full reference to all applicable rules, without using the words "Black Guard" to describe it. In my view, that's all that The Right Hand Of Darkness is looking for - particularly since you can't mix Black Guard with, for example, Executioners, Sisters of Slaughter or Corsairs. If you can't call it a unit of Black Guard, then what is it?

If we're going to look at quantities within the combined unit in order to determine whether The Right Hand Of Darkness applies, more than 50% of that unit is composed of models from the Black Guard entry in the Dark Elves army book (in the example you've given, at least). If it has any attribute, it's "Black Guard". Does it need to be 100% Black Guard models (other than Kouran) to be "Black Guard"? Where is the limit?

There is no answer in the books to this question. In asking it, however, we are departing from a rules-based analysis and instead asking "What can change the nature of a unit?"

[Calisson]

Good explanation of where we disagree.
And you still fail to explain why a combined unit should have the same nature as one of the units being part of it.

In asking it, however, we are departing from a rules-based analysis and instead asking "What can change the nature of a unit?"

20 BG is an army book entry. Its properties are described in DE AB.
20 BG + 12 characters is a combined unit. Its properties are described in BRB p.99.

Inside that 32 models combined unit, the 20 BG unit did not change its nature.
But we are no longer considering that 20 BG unit, we are now considering the 32 models.

[Taijushue]

I am going to have to agree with Calisson, technically a unit of 20 BG and 12 characters is, 13 units combined into 1, 1 unit of BG and 12 individual units of characters. This forms the combined unit. A combined unit is just that, it is not a unit of BG it is not a unit of Characters. It is a combined unit with multiple profiles. As a whole it ceases to be a unit of BG which only affects the rules for Kouran, this does not mean that they lose the special rules for BG because those are the rules of the individual models.

[Haagrum]

Some quick counter-examples, for those who have the Vampire Counts and End Times: Nagash books.

In Nagash Book 2, there is a rule, Tunnel Fighters, which applies to certain types of units in a couple of scenarios and protects such units from the effects of several Darkest Depths game rules. There is also an example of a named unit of Hammerers which becomes Unbreakable if joined by a particular character.

In the VC army list, Heinrich Kemmler's Chaos Tomb Blade gives him +2 Attacks. The second effect of Heinrich Kemmler's Chaos Tomb Blade is subject to the condition "if Kemmler is in a unit of Skeleton Warriors or Grave Guard" and lets him raise more models for each enemy model killed in close combat.

Applying the reasoning advanced by some, a unit ceases to be identifiable as a particular unit when it is joined by one or more characters. This is clearly a binary issue, given the emphasis on the "combined unit" rules which apply as soon as a character (or model which joins a unit like a character) joins a unit. One, ten, fifteen characters - it doesn't matter how many, as long as it's not zero. People have used the "20 Black Guard and 12 characters" example above, but you can change the 12 to any whole number above zero and this reasoning results in the same outcomes.

In the scenarios outlined above, this reasoning would lead to the following conclusions:

1. Tunnel Fighter units joined by a character of any kind would instantly lose Tunnel Fighter status. Suddenly, the environment becomes hazardous for them (for example, they can be hit by Cave-Ins, subject to Dangerous Terrain tests, or suffer hits from Falling Stalactites), purely because a character has joined the unit.

2. The Unbreakable Hammerers (referred to as the Blackhammers in both the scenario rules and the army selection description, so there's no question of misdescription) would lose the benefits of being Unbreakable immediately, since the Hammerer unit becomes Unbreakable but the specific character who joined the unit and conferred the rule does not.

3. The second effect of the Chaos Tomb Blade has absolutely no effect, since the unit can't be a unit of Skeleton Warriors or Grave Guard if Kemmler is in it.

These are quite clearly absurd outcomes.

[Calisson]

Applying the reasoning advanced by some, a unit ceases to be identifiable as a particular unit when it is joined by one or more characters.

Who did ever say anything like that?
As of myself, I wrote clearly that inside a combined unit, the BG part is still identifiable as a unit of BG.

The real absurdity is to extend the fact of being BG to the characters joining them. No rule, no logics support that.
With such absurdity, in your example 1, you would make a dragon immune to tunnel dangers because his rider would have joined Tunnel Fighters? Really?

[Red...]

It seems like there are several tiers to this:

- A unit of BG is a unit of BG: No controversy there
- A unit of BG plus a Kouran: is this still a unit of BG? If not, does Kouran confer his special ability even though it is a combined unit?
- A unit of BG plus any other character: is this still a unit of BG?
- A unit of BG plus Kouran plus one or more other characters: is this still a unit of BG? If not, does Kouran confer his special ability even though it is a combined unit?
- A unit of BG plus a model with a larger footprint (e.g. a Cauldron of Blood): is still still a unit of BG?
- A unit of BG plus Kouran plus a model with a larger footprint (e.g. a Cauldron of Blood): is this still a unit of BG? If not, does Kouran confer his special ability even though it is a combined unit?



To me, the only really clear RAW tier is the first: a unit of BG is a unit of BG. After that, it becomes increasingly RAI.

It is worth highlighting p100: "Special Rules: Unless otherwise noted in the text of the rule itself, a special rule applying only to a character does not apply to the unit, and vice versa. Most special rules are there to represdent specific skills or powers - you couldn't learn to shoot a longbow by standing next to someone who could, so why would you become able to perform a Killing Blow, deploy as a Scout, and so on? On the other hand, many spells and magic items bestow special rules and other effects on units. In this case, everyone (including the character) in the combined unit will be affected." I don't think it clarifies the answer, but illuminates a relevant block of text.

[direweasel]

- A unit of BG is a unit of BG: No controversy there

Obvious

- A unit of BG plus a Kouran: is this still a unit of BG? If not, does Kouran confer his special ability even though it is a combined unit?

If it's not, then Kouran's special ability is completely meaningless. I think it's clear that a BG unit led by Kouran is still a BG unit.

- A unit of BG plus any other character: is this still a unit of BG?

Kouran doesn't seem any different than any other character on foot. If Kouran's existence in the unit doesn't change the unit to a "combined" unit, then there's no reason not to think this is also the case for other characters. A unit led by any other character on foot is still a BG unit.

- A unit of BG plus Kouran plus one or more other characters: is this still a unit of BG? If not, does Kouran confer his special ability even though it is a combined unit?

This one is tricky, but to me, this is where the text of Kouran's ability comes into play. "he and all models in that unit have the Unbreakable special rule." Why would they put this text in here, if it wasn't to cover this exact scenario?

The "larger footprint models" part I'm intentionally omitting, because that's deeper in the weeds than I want to go. I almost regret typing this response already.

[Calisson]

- A unit of BG plus a Kouran: is this still a unit of BG?

=> I don't know any rule which would indicate that, RAW or RAI - except if you take the fluff into account.
IAW p.99, it is a combined unit, with two components: a unit of BG, and Kouran.

If not, does Kouran confer his special ability even though it is a combined unit?

=> Yes, by RAW.
Kouran's "The Right Hand Of Darkness" rule states "If Kouran Darkhand is in a unit of Black Guard, he and all models in that unit have the Unbreakable special rule."
In the combined unit, two components get the Unbreakable special rule:
- "he", which refers to "Kouran Darkhand";
- and "that unit", which refers to "a unit of Black Guard".

- A unit of BG plus any other character: is this still a unit of BG?

Not RAW, not RAI, not even fluff.
Not even common sense: A unit of cavalry plus any footlogger: is it still a unit of cavalry?

-=-=-

What is RAW is that in a combined unit, anything which is neither Kouran nor "a model in a unit of BG" will not become unbreakable.
What is certain is that joining a unit of BG does not make a character a BG himself.

The wish of many is that a unit could be considered as a unit of BG, even if there were non-BG models in it.
Direweasel seems willing to demonstrate that if it was not the case, Kouran's special rule would be useless.
Unfortunately for his demonstration, the fact that Kouran is not a BG, and the combined unit not to be a unit of BG itself, does not prevent his special rule to work.

[direweasel]

Calisson, as far as I'm concerned, you may be granted an honorary doctorate in rules lawyer college. I have no wish to go toe to toe with you in this debate.

Have fun.