Returning to Naggaroth

[Fingol23]

The question I have is how a Druchii would attain a position of power or prestige in Naggaroth without being born into it. In this case it is a Druchii who has lived outside of Naggaroth for a long time but I would think the same would apply to a Druchii born into a lesser noble house who seeks advancement.

[Dalamar]

Druchii born outside of Naggaroth? There's only one other possibility, on board of one of the Black Arks... But they are essentially moving part of Naggaroth

So truly, it only matters what family he was born into.

But remember that long time spent outside the courts in Naggaroth will mean that this druchii is badly versed in politics and underhanded dealings of the druchii nobility so he'd most probably don't fare too well no matter his birth.

[Ranieth]

Connection to someone powerful is the key I would say. As such I would go for being adopted or supported by a more powerful house.
Perhaps being granted a writ of iron as described in the army book and working from there would be a neat idea.