Time Sieve
Biotransference
Helm of the Host
Lena, Selfless Champion

   Prerequisites

What do I need to start this combo?
All permanents on the battlefield.
Helm of the Host attached to Lena. You control at least four nontoken creatures.

   Steps

How does this combo work?
1
At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Lena with haste.
2
The Lena token triggers, creating a number of 1/1 Soldier creature tokens equal to the number of nontoken creatures you control.
3
Activate Time Sieve by tapping it and sacrificing five creature tokens, causing you to take an extra turn after this one.
4
Repeat each turn.

   Results

What do I get from this combo?
Lock
Infinite turns