Having the ability for a keeper to designate one of his creatures as his avatar/dungeon lord etc could present some interesting opportunities in game.
Here are some suggestions:
1) Creatures of the same type will be happier knowing that one of their own is the Dungeon Lord/ Avatar etc.
2) Creatures who hate creatures of that type matching the Dungeon Lord/ Avatar will be unhappier.
3) A creature selected as the Lord will gain slight stat increases, immunity to some spells and possibly a unique spell (provide health bonus to those around him). He could also insist on his own lair, increased wage and possibly become lazier as he succumbs to stardom. Perhaps even refusing to use rooms occupied by 'lesser' creatures.
4) The death of a dungeon lord could cause nearby creatures to lose morale and flee and would make all creatures (who didn’t hate him) unhappy.
5) A creature marked as a dungeon lord could be recognised by a flaming aura (diablo style) or crown above the head, no massive graphical make overs needed.
I've played DK1 & 2 for years and often found myself with favoured creatures (usually horned reapers from DK1) with their own lairs and dungeon sections etc.
Regards
Acid