Boromir, Warden of the Tower + Knowledge Pool

Boromir, Warden of the Tower

Knowledge Pool

How it works

1. Whenever a player casts a spell from their hand, Knowledge Pool triggers, exiling the spell and allowing the player to cast another card exiled by Knowledge Pool without paying its mana cost.
2. If the player chooses to cast a spell, Boromir triggers, countering that spell since no mana was spent to cast it.