well, I only have 1 boss left for that, that is very first one so I really puzzled.
it contains some undead and ghost bosses and they lined by levels, from lower to higher dungeons
and second one was drowned corpse in sanctum, so I gave a try to black castle but got no update..
I assumed it could be lower leveled dungeon (or dungeon at low level playfield-such as imirian ravine, but did not get update as well and these dungeons never gave anything :s really abandoned contents )
so any clues about first boss in paladin achievement?