Activate Spark Double using Avatar Kuruk's ability by paying {20} minus {1} for each creature and/or artifact you can tap while activating it, causing you to take an extra turn after this one.
At the beginning of your end step, Don & Leo triggers, blinking Spark Double. Choose to have it enter the battlefield as a copy of Avatar Kuruk.
Repeat each turn.

Infinite turns

Lock

The Legend of Kuruk // Avatar Kuruk

Don & Leo, Problem Solvers

Spark Double

Activate Avatar Kuruk by paying {20} minus {1} for each creature and/or artifact you can tap while activating it, causing you to take an extra turn after this one.
At the beginning of your end step, Don & Leo triggers, blinking Avatar Kuruk and causing it to return to the battlefield as The Legend of Kuruk. Choose to have it enter with three lore counters due to its read-ahead ability given to it by Barbara Wright.
The Legend of Kuruk's third chapter ability triggers, causing you to exile it and return it to the battlefield as Avatar Kuruk.
Repeat.

Barbara Wright

Activate Marvin using Avatar Kuruk's ability by paying {20} minus {1} for each creature and/or artifact you can tap while activating it, causing you to take an extra turn after this one.
At the beginning of your end step, Don & Leo triggers, blinking Marvin.
Repeat each turn.

Combos with "Don & Leo, Problem Solvers"