Hero card

Betrayal at the Vault

Instant

SpellUsed once: what it does depends on when you cast it

Needs: Valiant, Big Mana

Gives: Spells

Not in winning lists yet: read from the card text and the graph

Build a deck with Betrayal at the Vault as the hero

Makes it work

Emberheart Challenger · Whiskervale Forerunner · Veteran Guardmouse · Nettle Guard · Mouse Trapper · Whiskerquill Scribe · Seedglaive Mentor · Flowerfoot Swordmaster

Benefits from it

Primeval Bounty

Use instead if you don't have it

Elemental Teachings · Homesickness · Mirrorform · Time Stop · Raphael's Technique · Zuko's Exile

Cards in the meta that answer it

Countersculpt (Azorius Control) · Inevitable Defeat (4-Color Control) · No More Lies (Azorius Control) · We Say Thee Nay! (Dimir Aggro)