Karrthus, Tyrant of Jund
Legendary Creature — Dragon
Flying, haste
When Karrthus enters, gain control of all Dragons, then untap all Dragons.
Other Dragon creatures you control have haste.
Don't fear death. Fear Karrthus.
Sam Burley
Secret Lair Drop (SLD)
• #1250Rulings
When the triggered ability resolves, you'll untap all Dragons, including the ones you already control.
(wotc • 2020-08-07)
The control-change effect of Karrthus's triggered ability lasts indefinitely. It doesn't wear off during the cleanup step, and it doesn't expire if Karrthus leaves the battlefield. In a multiplayer game, it does expire if you leave the game.
(wotc • 2020-08-07)
Rulings
When the triggered ability resolves, you'll untap all Dragons, including the ones you already control.
(wotc • 2020-08-07)
The control-change effect of Karrthus's triggered ability lasts indefinitely. It doesn't wear off during the cleanup step, and it doesn't expire if Karrthus leaves the battlefield. In a multiplayer game, it does expire if you leave the game.
(wotc • 2020-08-07)