Death knight is a decent character . But i think a nephalem Must not be tottally dead or villainWizards has some far East inspiring too
A Semi reaped soulHe is not alive or death , he is both ...
Life bar has two parts : human / deathWhen life falls below a line character passes to death form
Human form is a warrior knight or a samurai inpired style warriorDeath form is a spirit combatant and necromancer , bone magician
Intelligence feeds the death part of the life bar strength or vitality feeds human partMaybe some passive and active abilities can perform or autoperform on the transformation line
Special items : samurai masks , multiple katana sword packs , flags on pauldrons for some special affixes