Card

Sanguine Bond

Mana cost {3}{B}{B}

Whenever you gain life, target opponent loses that much life.

Part of 26 known combos, 6 of them two-card. 5 official rulings.

Bracket

B1 Exhibition — Not in the same deck as its two-card combo partners: Exquisite Blood, Bloodthirsty Conqueror, Beacon of Immortality, Revival // Revenge, Shard of the Nightbringer, Enduring Angel // Angelic Enforcer
B2 Core — Not in the same deck as its two-card combo partners: Exquisite Blood, Bloodthirsty Conqueror, Beacon of Immortality, Revival // Revenge, Shard of the Nightbringer, Enduring Angel // Angelic Enforcer
B3 Upgraded — Not in the same deck as its early two-card combo partners: Exquisite Blood, Bloodthirsty Conqueror, Beacon of Immortality, Enduring Angel // Angelic Enforcer
B4 Optimized — allowed: No restriction beyond the banned list
B5 cEDH — allowed: No restriction beyond the banned list

Two-card combo with Exquisite Blood, Bloodthirsty Conqueror, Beacon of Immortality, Revival // Revenge, Shard of the Nightbringer, Enduring Angel // Angelic Enforcer (early with Exquisite Blood, Bloodthirsty Conqueror, Beacon of Immortality, Enduring Angel // Angelic Enforcer)

Bracket: Lotus Vault analysis, with Commander Spellbook flags

26 known combos, 6 of them two-card.

Sanguine Bond + Exquisite Blood
Produces: Infinite lifegain triggers, Infinite lifeloss, Infinite lifegain
View on Commander Spellbook
Sanguine Bond + Bloodthirsty Conqueror
Produces: Infinite lifegain triggers, Infinite lifeloss, Infinite lifegain
View on Commander Spellbook
Beacon of Immortality + Sanguine Bond
Produces: Target opponent loses the game
View on Commander Spellbook

2024-04-12 · Wizards of the Coast
In a Two-Headed Giant game, life gained by your teammate won't cause Sanguine Bond's ability to trigger, even though it caused your team's life total to increase.
2023-09-01 · Wizards of the Coast
Each creature with lifelink dealing combat damage causes a separate life-gaining event. For example, if two creatures you control with lifelink deal combat damage at the same time, Sanguine Bond's ability will trigger twice and you may choose a different opponent for each trigger. However, if a single creature you control with lifelink deals combat damage to multiple creatures, players, planeswalkers, and/or battles at the same time (perhaps because it has trample or was blocked by more than one creature), the ability will trigger only once.
2021-03-19 · Wizards of the Coast
If you gain an amount of life "for each" of something, that life is gained as one event and Sanguine Bond's ability triggers only once.
2021-03-19 · Wizards of the Coast
If an ability triggers whenever an opponent loses life and causes you to gain life, such as the ability of Exquisite Blood, this will loop until either you win the game or a player takes an action to break the loop. If neither of these happen, the game ends in a draw.
2009-10-01 · Wizards of the Coast
Sanguine Bond's ability triggers just once for each life-gaining event, whether it's 1 life from Soul Warden or 8 life from Tendrils of Corruption.

Rulings: Scryfall · Wizards of the Coast