Cursed enemy absorption

Cursed Enemy Manipulation: As the name implies, The Spell allows him to control an enemy's spirit once they've been defeated by The caster in battle. Dominated enemies are turned into small black orbs by being touched by the caster that he must ingest orally in order to use. If the difference in power is more than two levels, The caster can absorb the enemy within the black orb with no consequences. If the enemy is his level or a level higher then The caster, The caster have mild effects such as a exhaustion level 1 for a day. If the difference in level is multiple above The caster then there will be more serious effect such as exhaustion level 2 - 4 and possible effects like blindness or deafness for multiple days. The casters enemies are weaker then before they became The caster's familiar, though they can get stronger overtime. people who can use magic remain able to use it.

[Custom leveling system is you want to use it instead of using D&D levels]
4th Grade (Levels 1 - 5)
3rd Grade ( Levels 6 - 9)
2nd Grade (Levels 10 - 14) 
1st Grade (Levels 15 - 17)
Special Grade (Levels 18-20)