Activate Warren Soultrader by paying 1 life and sacrificing the persist creature.
When the persist creature dies, its persist ability triggers, returning the persist creature from your graveyard to the battlefield with a -1/-1 counter on it.
When the persist creature enters, Soul Warden triggers, causing you to gain 1 life.
Resolve the Warren Soultrader ability, creating a Treasure token.
When the Treasure enters, Mm'menon triggers, putting a +1/+1 counter on the persist creature.
Repeat.
This ingenious loop turns a fragile cycle of life and decay into a self-sustaining engine of infinite resources. At the heart of it all is Warren Soultrader, which provides the sacrifice outlet needed to fuel the loop while generating a Treasure token every time a creature meets its end. To keep your life total from draining away, Soul Warden steps in to offset the cost by granting you life with every creature that returns to the battlefield. Meanwhile, Mm'menon, Uthros Exile watches over your artifacts, placing a +1/+1 counter on your creature whenever that newly minted Treasure enters the battlefield to instantly neutralize any accumulated -1/+1 counters and keep the entire chain moving indefinitely.