You control another nontoken creature with base toughness 2 or greater that does not have a -1/-1 counter on it.
Steps
Activate
Bloodthrone Vampire by sacrificing the additional creature.
When the creature dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
Resolve the
Bloodthrone Vampire ability.
Activate
Bloodthrone Vampire by sacrificing
Sin.
When
Sin dies, it triggers twice.
Resolve the first trigger, returning
Sin from your graveyard to the battlefield with a -1/-1 counter on it. As
Sin enters, remove the -1/-1 counter from the creature sacrificed in step 1, causing
Sin to enter with a +1/+1 counter on it instead.
Resolve the second
Sin trigger, putting the counters it had on it when it was sacrificed onto a creature you control and failing to shuffle it into your library as it's no longer in your graveyard.
Resolve the
Bloodthrone Vampire ability from step 4.
Repeat.
Results
Infinite +1/+1 counters on creatures you control.
Infinite creature ETB.
Infinite creature LTB.
Infinite creature sacrifice triggers.
Infinite death triggers.
Infinitely large creature until end of turn.
Metadata
Bracket tag
ExhibitionBracket 1+
For any deck
1
2
3
4
5
1 · Exhibition5 · cEDH
Bracket tags are estimated from the cards and results of each combo, as a guideline rather than a strict classification.