Greenwarden of Murasa
Creature — Elemental
When this creature enters, you may return target card from your graveyard to your hand.
When this creature dies, you may exile it. If you do, return target card from your graveyard to your hand.
Eric Deschamps
Battle for Zendikar (BFZ)
• #174Rulings
You decide whether to exile Greenwarden of Murasa as the last ability resolves. Players can respond to this ability triggering, but once it starts resolving and you decide to exile Greenwarden of Murasa, it's too late for anyone to respond.
(wotc • 2015-08-25)
If the target card becomes illegal before the last ability resolves, it won't resolve. You can't exile Greenwarden of Murasa in that case, even if you want to.
(wotc • 2015-08-25)
Rulings
You decide whether to exile Greenwarden of Murasa as the last ability resolves. Players can respond to this ability triggering, but once it starts resolving and you decide to exile Greenwarden of Murasa, it's too late for anyone to respond.
(wotc • 2015-08-25)
If the target card becomes illegal before the last ability resolves, it won't resolve. You can't exile Greenwarden of Murasa in that case, even if you want to.
(wotc • 2015-08-25)