Sigurd, Jarl of Ravensthorpe, Time Sieve, There and Back Again, and City of Death

Prerequisites

• Sigurd, Jarl of Ravensthorpe on the battlefield
• Time Sieve on the battlefield
• There and Back Again on the battlefield
• City of Death on the battlefield
• There and Back Again has exactly two lore counters on it
• City of Death has between one and four lore counters on it
• An opponent cannot block and kill Sigurd

Steps

1. At the beginning of your precombat main phase, There and Back Again and City of Death trigger
2. Resolve the There and Back Again trigger, putting a lore counter on it
3. There and Back Again's third chapter ability and Sigurd trigger
4. Resolve the Sigurd trigger, putting a +1/+1 counter on a creature you control
5. Resolve the There and Back Again trigger, creating a legendary 6/6 Smaug creature token and causing you to sacrifice There and Back Again
6. Resolve the City of Death trigger, putting a lore counter on it
7. City of Death's second chapter ability and Sigurd trigger
8. Resolve the Sigurd trigger, putting a +1/+1 counter on a creature you control
9. Resolve the City of Death trigger, creating a copy of the Smaug token
10. Put a Smaug token into your graveyard due to the legend rule
11. When the Smaug token dies, it triggers, creating fourteen Treasure tokens
12. Declare Sigurd as an attacker
13. Activate a Treasure by tapping and sacrificing it, adding
14. Activate Sigurd by paying , removing a lore counter from City of Death
15. Activate Time Sieve by tapping it and sacrificing five Treasures, causing you to take an extra turn after this one
16. Move to your next turn
17. At the beginning of your precombat main phase, City of Death triggers, putting a lore counter on it
18. Repeat from step 7

Results

• Infinite turns