Play Oathbreaker Online Free
Planeswalker as your commander. Signature spell as your closer. Test it free in your browser.
What is Oathbreaker?
Oathbreaker is a 60-card singleton format with a planeswalker as your "oathbreaker" (commander equivalent) plus a signature spell — an instant or sorcery that can only be cast with the planeswalker on the battlefield. Both start in the command zone. Decks are singleton; colour identity matches the planeswalker. Starting life total is 20 (vs. Commander's 40), making games shorter and the planeswalker's loyalty matter more.
The format is small but devoted. There aren't many places to play it online — most clients treat it as a Commander variant with manual setup, which is fine but inelegant.
Oathbreaker in TCG Playsim
First-class support: the deckbuilder has an Oathbreaker format option that splits out a planeswalker slot AND a signature spell slot. Both start in the command zone at game-start. The playtester knows the signature spell can only be cast while the oathbreaker is in play (you enforce this — the playtester is manual — but the visual layout makes it obvious).
Building an Oathbreaker deck
New Deck → format: Oathbreaker → set planeswalker → set signature spell → build the 58 other cards. Colour identity is the planeswalker's. Singleton rules apply (one of each non-basic). Most decks lean into either tutoring up the signature spell, protecting the oathbreaker, or both.
Multiplayer Oathbreaker
The format plays cleanly in 2 to 4 player rooms. Each player has their own oathbreaker + signature spell. Free-for-all is the default; politics is part of the meta.