Cast Blasphemous Act by paying at most {7}{R}, dealing 13 damage to each creature.
Each creature an opponent controls who was dealt dealt excess damage this way causes Toralf to trigger.
Resolve the first Toralf trigger, dealing an amount of damage to an opponent.
Repeat step 3 for each remaining trigger.

Near-infinite damage

Toralf, God of Fury // Toralf's Hammer

Blasphemous Act

Cast Star of Extinction by paying {5}{R}{R}, destroying target land and dealing 20 damage to each creature and each planeswalker.
Toralf triggers for each creature your opponent control that is dealt excess damage this way.
Resolve a Toralf trigger, dealing damage equal to the excess damage to any target.
Repeat step 3 for each remaining trigger.

Star of Extinction

Declare any creature as an attacker. Dawnsire triggers, dealing 100 damage to  a creature or planeswalker an opponent controls.
Toralf triggers, dealing daamge equal to the excess damage dealt in step 1 to any target.

Near-infinite damage to any target

Dawnsire, Sunstar Dreadnought

Activate Deathless Angel twice by paying {W}{W}{W}{W}, giving two creatures an opponent controls indestructible until end of turn.
Deal noncombat damage to one of the indestructible creatures, dealing an increased amount of damage instead due to City on Fire.
Toralf triggers, dealing an amount of damage over the excess damage to the second indestructible creature due to City on Fire.
Toralf triggers, dealing an amount of damage over the excess damage to the first indestructible creature due to City on Fire.
Repeat from step 3 an arbitrarily large number of times.
Resolve a Toralf trigger, dealing infinite damage to any target.

Infinite damage to any target

Deathless Angel

City on Fire

Cast Apex Altisaur by paying {7}{G}{G}.
When Apex Altisaur enters the battlefield, its first ability triggers.
Holding priority, activate Gyome twice by paying {2} and sacrificing two Foods, giving Apex Altisaur and any creature an opponent controls indestructible until end of turn.
Resolve the Apex Altisaur trigger, causing Apex Altisaur to fight the indestructible creature the opponent controls.
Apex Altisaur's second ability triggers, and Toralf triggers if the opposing creature's toughness is less than 0.
Resolve the Toralf trigger, if applicable, dealing damage equal to the excess to any target.
Resolve the Apex Altisaur trigger, causing it to fight the indestructible creature the opponent controls.
Repeat from step 5.

Infinite damage

Apex Altisaur

Gyome, Master Chef

Activate Deathless Angel twice by paying {W}{W}{W}{W}, giving two creatures an opponent controls indestructible until end of turn.
Cast Toralf by paying {2}{R}{R}.
Deal noncombat damage to one of the indestructible creatures.
Toralf triggers, dealing double the excess damage to the second indestructible creature due to Neriv.
Toralf triggers, dealing double the excess damage to the first indestructible creature due to Neriv.
Repeat from step 3 an arbitrarily large number of times.
Resolve a Toralf trigger, dealing infinite damage to any target.

Neriv, Heart of the Storm

Cast Apex Altisaur by paying {7}{G}{G}.
When Apex Altisaur enters the battlefield, its first ability triggers.
Holding priority, cast Ajani's Presence by paying {2}{W}{W}, giving Apex Altisaur and any creature an opponent controls +1/+1 and indestructible until end of turn.
Resolve the Apex Altisaur trigger, causing Apex Altisaur to fight the indestructible creature the opponent controls.
Apex Altisaur's second ability triggers, and Toralf triggers if the opposing creature's toughness is less than 0.
Resolve the Toralf trigger, if applicable, dealing damage equal to the excess to any target.
Resolve the Apex Altisaur trigger, causing it to fight the indestructible creature the opponent controls.
Repeat from step 5.

Combos with "Toralf, God of Fury // Toralf's Hammer"