User blog comment:Darksusanoo/Kassadin...his current state and possible rework ideas/@comment-8050014-20140918161235

The only problem I see here is the mana damage scaling on his W. Damage scaling on an enemy's mana only works when ALL champions have the same casting resource. Otherwise people will just take manaless mages like Vladimir and Kennen and be able to avoid a fair-sized chunk of his damage. I'm going to assume that you play DoTA 2, where this would work because all characters in DoTA use mana.