Cast Plague of Vermin by paying {6}{B}.
Resolve Plague of Vermin, choosing to pay all but one life and create that many black Rat tokens.
For each Rat tokens that enters the battlefield, Ayara triggers, causing you to gain that many life and each opponent to lose that many life.

Near-infinite creature tokens for all players

Near-infinite creature ETB

Near-infinite lifegain

Near-infinite lifegain triggers

Near-infinite lifeloss

Ayara, First of Locthwain

Plague of Vermin

Cast Plague of Vermin by paying {6}{B}, causing you to pay life equal to the highest life total your opponents have and create that many 1/1 Rat creature tokens.
Mirkwood Bats triggers for each token created this way, causing each opponent to lose that much life.
Each opponent loses the game due to having zero or less life.

Each opponent loses the game

Near-infinite creature tokens

Mirkwood Bats

Cast Plague of Vermin, paying at least as much life as the opponent with the highest life total has.
Resolve Plague Vermin, creating an amount of Rats equal to the amount of life you paid.
Corpse Knight triggers for each Rat, causing each opponent to lose 1 life for each Rat.

Corpse Knight

Cast Plague of Vermin by paying {6}{B} and choosing to pay any amount of life, creating that many 1/1 Rat creature tokens.
Activate Ashnod's Altar by sacrificing a Rat.
When the Rat dies, Nadier's Nightblade triggers, causing each opponent to lose 1 life and you to gain 1 life.
Repeat from step 2 as able.

Near-infinite creature LTB

Near-infinite death triggers

Near-infinite creature sacrifice triggers

Near-infinite colorless mana

Ashnod's Altar

Nadier's Nightblade

Cast Plague of Vermin by paying {6}{B}. Choose to pay an amount of life and create that many 1/1 Rat creature tokens.
Activate Ingris by paying {4}, creating a 2/2 Cadet creature token and giving creatures you control haste until end of turn.
Declare all eligible creatures you control as attackers.
Ingris triggers for each attacking creature, dealing that much damage to each opponent.

Near-infinite creature tokens with haste

Near-infinite damage

Ingris Stingerquill

Combos with "Plague of Vermin"