Vathah, Espionage Savant

Whenever you cast a blue spell, exile the top
card of target opponent's library.
Whenever you cast a black spell, exile the top
card of target opponent's library.
Your opponents can't cast spells with the same
name as a card exiled with Vathah, Espionage Savant.

based on Circu, Dimir Lobotomist