Hmmmmmmmmmmmmmm.... maybe make killing dangerous creatures like adventurers give a large portion of their XP? Also some sanity tweaks.
Name: Shadow
Appearance: A tangible shadow in humanoid form.
Personality: Hungry to kill the nearest 'good' aligned creature.
Preferences: Dark simple areas.
Default Actions: Killing, this can be done with animals, and similar category's.
Requirements: A dark rooms with at least some basic furniture.
Abilities: Reaving souls of almost dead mortals( This will increase their stats and skills in proportion to power of killed mortals so killing a imp isn't going to change him, but a human champion will.), scaring faint hearted by being made of shadows.
Attack: 3(+2)
Defense: 3
HP: 3(-1, I mean come on being made of tangible shadows probably isn't good for strength.)
Name: Miravex
Appearance: A typical tangible shadow in humanoid form, has markings in navy blue to show emotions, etc.
Personality: Bloodthirsty in combat, can act about dwarf fortress dorf level of sanity.
Preferences: Magic powers, people who aren't scared at a glimpse of him ,libraries ,dark rooms to rest in.
Default Actions: (Sane enough to not auto kill animals/lesser minions), help imps if there is nothing to do.
Requirements: A library, source of souls to reave ( Not constant, stuff like humans, animals) ,and a dark room to sleep in.
Abilities: Knows magical abilities that allows itself to harden its matter, makes it rather cocky when it comes to defense though. can also use these abilities to bolster its offense.Reaving souls of almost dead mortals( This will increase their stats and skills in proportion to power of killed mortals), being made of shadows naturally scares the faint hearted.
Attack: 3 (+2)
Defense: 3 (-1)
HP: 5