Yennett, Cryptic Sovereign + Doomsday + Nexus of Fate + Necropotence

Prerequisites

• Yennett does not have summoning sickness.
• An opponent cannot block and kill Yennett.
• Your life total is at least ten.

Steps

1. 1Cast Doomsday by paying , searching your library and graveyard for Nexus of Fate and four other cards, then exiling the rest of your library and graveyard, putting the aforementioned cards on top of your library with Nexus of Fate being the bottom card, and causing you to lose half your life total, rounded up.
2. 2Activate Necropotence four times by paying 4 life, exiling the top four cards of your library.
3. 3Declare Yennett as attacker.
4. 4Yennett triggers, casting Nexus of Fate from your library without paying its mana cost.
5. 5Resolve Nexus of Fate, causing you to take an extra turn after this one and shuffle Nexus of Fate into your library.
6. 6Repeat from step 3 each turn.

Effects

• Exile your library
• Infinite turns
• Lock