Oathbreaker

Oathbreaker consists of a 58 card singleton deck with 1 planeswalker and 1 signature spell in your command zone and 20 life total.
You may only cast your signature spell if your planeswalker is on the battlefield.
Each time you cast your planeswalker or signature spell after the first, it costs {2} more.
If your planeswalker or signature spell should go to the graveyard, it returns to the command zone.