Magar of the Magic Strings + Warrior's Oath + Glorious End

Magar of the Magic Strings

Warrior's Oath

Glorious End

How it works

1. Cast Warrior's Oath by paying its mana cost, causing you to take an extra turn after this one and to lose the game at the beginning of that turn's end step.
2. Activate Magar by paying 1, noting Warrior's Oath and putting it face down on the battlefield as a 3/3 creature.
3. Activate Magar by paying 1, noting Glorious End and putting it face down on the battlefield as a 3/3 creature.
4. During your next turn, deal combat damage to an opponent using the face down creatures that have Warrior's Oath and Glorious End noted. The creatures trigger.
5. Resolve the first trigger, casting a copy of Warrior's Oath without paying its mana cost. Resolve the copy, causing you to take an extra turn after this one and to lose the game at the beginning of that turn's end step.
6. Resolve the second trigger, casting a copy of Glorious End without paying its mana cost. Resolve the copy, causing you to end the turn. This will prevent the Warrior's Oath trigger from causing you to lose the game.
7. Repeat from step 3.

This loop lets you take infinite turns by weaponizing spells that would normally spell your doom. First, you use Magar of the Magic Strings to turn your graveyard's most dangerous instants and sorceries into 3/3 creatures. When those face-down attackers connect with an opponent, they generate free copies of Warrior's Oath for extra turns and Glorious End to abruptly cut your turns short. Ending the turn with Glorious End is the clever trick that saves you from Warrior's Oath's deferred game loss, letting you cycle through infinite extra turns safely.