Heartless Hidetsugu and Bitter Feud on the battlefield.
Yourself and an opponent with an even life total chosen with Bitter Feud.
Heartless Hidetsugu does not have summoning sickness.
Steps
Activate Heartless Hidetsugu by tapping it, causing it to deal damage to the opponent chosen by Bitter Feud equal to the opponent's life total, and to each other player equal to half their life total, rounded down.
The opponent chosen by Bitter Feud loses the game due to having zero or less life.