Activate Yawgmoth's first ability by paying 1 life and sacrificing another creature.
When the creature dies, Relic Vial triggers, causing you to gain 1 life and each opponent to lose 1 life.
Resolve the Yawgmoth ability, causing you to draw a card and allowing you to put a -1/-1 counter on up to one creature.
The Locust God triggers, creating a 1/1 Insect creature token with flying and haste.
Repeat.
This vicious loop runs on a self-sustaining engine where Yawgmoth, Thran Physician converts disposable fodder into card draw, which in turn feeds The Locust God's triggered ability to continuously manufacture fresh Insect tokens to be sacrificed right back into him. While Yawgmoth's sacrifice cost naturally offsets its own life payment, Relic Vial amplifies the entire exchange by weaponizing each death to drain your opponents and pad your life total. Together, this trio transforms the simple act of drawing cards into a lethal cascade that sweeps the board and ends the game on the spot.