A Karthus buff with his E passive
Right now he gains mana while E is off if he kills an enemy while he has a point in his E.
What if he gained souls for every kill while his E is off, stacking to 30 souls, and the souls do nothing except when he ults while he has souls, he does 1-2 more damage for each soul?
So basically, if he had 30 souls and he ulted, he will do an additional 30-60 damage with his ult but he then expends all of his souls.
Thoughts?