Activate Ashnod's Altar by sacrificing Su-Chi, adding CC.
When Su-Chi dies, it triggers, adding CCCC.
Activate Chainer by paying 3 and 3 life, returning Su-Chi to the battlefield from your graveyard.
When Su-Chi enters the battlefield, Trostani triggers, causing you to gain life equal to Su-Chi's toughness.
Repeat.
This ingenious loop relies on Ashnod's Altar and Chainer, Dementia Master working in tandem to repeatedly recycle Su-Chi through the graveyard, fueling Chainer's activation cost while generating an excess of mana. Mycosynth Lattice plays a quiet yet vital foundational role here, turning all permanents and cards into artifacts and making everything colorless so you can freely spend that generated mana on Chainer's black-heavy requirements. Meanwhile, Trostani, Selesnya's Voice turns every iteration of Su-Chi reentering the battlefield into a steady stream of lifegain, ensuring your life total can easily weather Chainer's repeated 3-life toll.