Blood Tyrant — ruling 1

Blood Tyrant’s second ability causes each player to lose 1 life, including you. Blood Tyrant will count each player’s life loss, including yours, when determining how many +1/+1 counters it gets.

Blood Tyrant — ruling 2

Blood Tyrant’s third ability will trigger no matter how a player loses the game: due to a state-based action (as a result of having a life total of 0 or less, trying to draw a card from an empty library, or having ten poison counters), a spell or ability that says that player loses the game, a concession, or a game loss awarded by a judge.

Blood Tyrant — ruling 3

In a multiplayer game using the limited range of influence option (such as a Grand Melee game), if a spell or ability says that you win the game, it instead causes all of your opponents within your range of influence to lose the game. This is another way by which Blood Tyrant’s third ability can trigger.

Blood Tyrant : règles, fonctionnement et interactions (MTG)

Blood Tyrant is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Flying, trample At the beginning of your upkeep, each player loses 1 life. Put a +1/+1 counter on this creature for each 1 life lost this way. Whenever a player loses the game, put five +1/+1 counters on this creature.

How it works : Blood Tyrant

Original English text — Wizards of the Coast / Scryfall

#1February 1, 2009· Wizards of the Coast
Blood Tyrant’s second ability causes each player to lose 1 life, including you. Blood Tyrant will count each player’s life loss, including yours, when determining how many +1/+1 counters it gets.
No other card is named in this ruling.
#2February 1, 2009· Wizards of the Coast
Blood Tyrant’s third ability will trigger no matter how a player loses the game: due to a state-based action (as a result of having a life total of 0 or less, trying to draw a card from an empty library, or having ten poison counters), a spell or ability that says that player loses the game, a concession, or a game loss awarded by a judge.
No other card is named in this ruling.
#3February 1, 2009· Wizards of the Coast
In a multiplayer game using the limited range of influence option (such as a Grand Melee game), if a spell or ability says that you win the game, it instead causes all of your opponents within your range of influence to lose the game. This is another way by which Blood Tyrant’s third ability can trigger.
No other card is named in this ruling.