Dovin, Hand of Control
Legendary Planeswalker — Dovin
Artifact, instant, and sorcery spells your opponents cast cost 
more to cast.
-1
: Until your next turn, prevent all damage that would be dealt to and dealt by target permanent an opponent controls.
Kieran Yanner
War of the Spark (WAR)
• #229Rulings
Once Dovin’s loyalty ability resolves, the damage prevention continues to apply even if Dovin leaves the battlefield.
(wotc • 2019-05-03)
In a multiplayer game, if you leave the game after Dovin’s last ability resolves but before your next turn begins, its effect lasts until your next turn would have begun. It neither expires immediately nor lasts indefinitely.
(wotc • 2019-05-03)
Dovin’s loyalty ability can target any permanent an opponent controls, not just one that can deal or be dealt damage.
(wotc • 2019-05-03)
Rulings
Once Dovin’s loyalty ability resolves, the damage prevention continues to apply even if Dovin leaves the battlefield.
(wotc • 2019-05-03)
In a multiplayer game, if you leave the game after Dovin’s last ability resolves but before your next turn begins, its effect lasts until your next turn would have begun. It neither expires immediately nor lasts indefinitely.
(wotc • 2019-05-03)
Dovin’s loyalty ability can target any permanent an opponent controls, not just one that can deal or be dealt damage.
(wotc • 2019-05-03)