Cast Slaughter Pact, choosing to pay its replicate cost at least ten times per opponent you have, by paying a total of {0}, targeting Venerated Rotpriest.
Venerated Rotpriest and Slaughter Pact's replicate ability trigger.
Resolve the Slaughter Pact trigger, creating a copy for each time its replicate cost was paid, with each copy targeting Venerated Rotpriest.
Venerated Rotpriest triggers for each copy targeting it this way.
Resolve the first Venerated Rotpriest trigger, causing an opponent to get a poison counter.
Repeat step 5 until the opponent loses the game due to having ten poison counters.
Repeat from step 5 for each remaining opponent.

Each opponent loses the game

Infinite magecraft triggers

Venerated Rotpriest

Slaughter Pact

Djinn Illuminatus

Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
Cast Semester's End by paying {3}{W}, targeting every creature you control.
Venerated Rotpriest triggers for each creature targeted by Semester's End.
Resolve the first trigger, causing an opponent to get a poison counter.
Repeat step 4 until an opponent loses the game due to having ten poison counters, then repeat for each other opponent.

Storm Herd

Semester's End

Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
Cast Sylvan Paradise by paying {G}, targeting every creature you control.
Venerated Rotpriest triggers for each creature targeted by Sylvan Paradise.
Resolve the first trigger, causing an opponent to get a poison counter.
Repeat step 4 until an opponent loses the game due to having ten poison counters, then repeat for each other opponent.

Sylvan Paradise

Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
Cast Scapegoat by paying {W} and sacrificing a Pegasus, targeting every creature you control.
Venerated Rotpriest triggers for each creature targeted by Scapegoat.
Resolve the first trigger, causing an opponent to get a poison counter.
Repeat step 4 until an opponent loses the game due to having ten poison counters, then repeat for each other opponent.

Scapegoat

Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
Cast Eerie Interlude by paying {2}{W}, targeting every creature you control.
Venerated Rotpriest triggers for each creature targeted by Eerie Interlude.
Resolve the first trigger, causing an opponent to get a poison counter.
Repeat step 4 until an opponent loses the game due to having ten poison counters, then repeat for each other opponent.

Eerie Interlude

Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
Cast Heaven's Gate by paying {W}, targeting every creature you control.
Venerated Rotpriest triggers for each creature targeted by Heaven's Gate.
Resolve the first trigger, causing an opponent to get a poison counter.
Repeat step 4 until an opponent loses the game due to having ten poison counters, then repeat for each other opponent.

Heaven's Gate

Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
Cast Dwarven Song by paying {R}, targeting every creature you control.
Venerated Rotpriest triggers for each creature targeted by Dwarven Song.
Resolve the first trigger, causing an opponent to get a poison counter.
Repeat step 4 until an opponent loses the game due to having ten poison counters, then repeat for each other opponent.

Dwarven Song

Cast Rancor by paying {G}, or by paying two life due to Defiler of Vigor, targeting Defiler of Vigor.
Defiler of Vigor and Venerated Rotpriest triggers.
Resolve the Defiler of Vigor trigger, putting a +1/+1 counter on each creature you control.
Resolve the Venerated Rotpriest trigger, causing an opponent to get a poison counter.
If the opponent has ten poison counters, they lose the game as a state-based action.
Activate Gatherer of Graces by sacrificing Rancor.
Rancor triggers, returning itself to your hand from your graveyard.
Resolve the Gatherer of Graces ability, regenerating it.
Repeat until each opponent loses the game due to having ten poison counters.

Near-infinite +1/+1 counters

Near infinite storm count

Gatherer of Graces

Defiler of Vigor

Rancor

Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
Cast Cauldron Haze by paying {1}{W/B}, targeting every creature you control.
Venerated Rotpriest triggers for each creature targeted by Cauldron Haze.
Resolve the first trigger, causing an opponent to get a poison counter.
Repeat step 4 until an opponent loses the game due to having ten poison counters, then repeat for each other opponent.

Cauldron Haze

Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
Cast any instant or sorcery by paying its mana cost, targeting Zada.
Zada and Venerated Rotpriest trigger.
Resolve the Venerated Rotpriest trigger, causing an opponent to get a poison counter.
Resolve the Zada trigger, copying the spell for each other creature you control, with each copy targeting a different creature.
Venerated Rotpriest triggers for each copy made this way.
Resolve the first trigger, causing an opponent to get a poison counter.
If the opponent has ten poison counters, they lose the game.
Repeat from step 7 for each remaining trigger.

Zada, Hedron Grinder

Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
Cast Sway of Illusion by paying {1}{U}, targeting every creature you control.
Venerated Rotpriest triggers for each creature targeted by Cauldron Haze.
Resolve the first trigger, causing an opponent to get a poison counter.
Repeat step 4 until an opponent loses the game due to having ten poison counters, then repeat for each other opponent.

Sway of Illusion

Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
Cast Touch of Darkness by paying {B}, targeting every creature you control.
Venerated Rotpriest triggers for each creature targeted by Touch of Darkness.
Resolve the first trigger, causing an opponent to get a poison counter.
Repeat step 4 until an opponent loses the game due to having ten poison counters, then repeat for each other opponent.

Touch of Darkness

Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
Cast any instant or sorcery by paying its mana cost, targeting Mirrorwing Dragon.
Mirrorwing Dragon and Venerated Rotpriest trigger.
Resolve the Venerated Rotpriest trigger, causing an opponent to get a poison counter.
Resolve the Mirrorwing Dragon trigger, copying the spell for each other creature you control, with each copy targeting a different creature.
Venerated Rotpriest triggers for each copy made this way.
Resolve the first trigger, causing an opponent to get a poison counter.
If the opponent has ten poison counters, they lose the game.
Repeat from step 7 for each remaining trigger.

Mirrorwing Dragon

Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
Cast Energy Arc by paying {W}{U}, targeting every creature you control.
Venerated Rotpriest triggers for each creature targeted by Energy Arc.
Resolve the first trigger, causing an opponent to get a poison counter.
Repeat step 4 until an opponent loses the game due to having ten poison counters, then repeat for each other opponent.

Energy Arc

Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
Cast Sea Kings' Blessing by paying {U}, targeting every creature you control.
Venerated Rotpriest triggers for each creature targeted by Sea Kings' Blessing.
Resolve the first trigger, causing an opponent to get a poison counter.
Repeat step 4 until an opponent loses the game due to having ten poison counters, then repeat for each other opponent.

Combos with "Venerated Rotpriest"