1 Apr 2008
If a split card is turned face up, the ability counters all spells with the same name as either side of that split card.
1 Apr 2008
The only cards you turn face up are the cards exiled with the Grimoire Thief that was sacrificed.
1 Apr 2008
The last ability counters all spells on the stack with any of the appropriate names, no matter who controls them.
1 Jul 2013
Once a player is allowed to look at the exiled face-down cards, that player may continue to do so even after Grimoire Thief leaves the battlefield or another player gains control of it.
1 Jul 2013
Once a player gains control of Grimoire Thief, that player can look at all cards it exiled, even if those cards were exiled while someone else controlled Grimoire Thief.