Resolve Grave Pact's ability, causing each other player to sacrifice a creature.
Glissa triggers once for each creature that dies this way, causing you to return Su-Chi (and possibly additional artifact cards) from your graveyard to your hand.
Cast Su-Chi by paying ({4} magic symbol) .
Repeat until your opponents control no creatures.
Repeat each turn.
Results
Near-infinite colorless mana.
Near-infinite death triggers.
Near-infinite ETB.
Near-infinite LTB.
Near-infinite sacrifice triggers.
Near-infinite storm count.
Opponents sacrifice all their creatures every turn.