If you are using it defensively to protect your own spells on your turn, I would cast it in your second main phase, especially if you do not care about attacking
Mana symbols on a transforming double-faced permanent's front face don't count toward your devotion to any color while it's on the battlefield with its back face up
Casting Cost: Card Type: Artifact Card Text: , Discard two cards: Draw three cards, then put a fuse counter on this artifact
Consequently, the fact that Death's Majesty makes all Zombie creatures is very good since her ultimate becomes a one-sided board wipe that will likely win you the game on the spot
But for other Rooms where both abilities are one-use, or more context-dependent effects, there will likely be a dynamic choice about which order to unlock the doors every time theyre played
The Lost Caverns of Ixalan Card Image Gallery Card Image Gallery / The Lost Caverns of Ixalan done The Lost Caverns of Ixalan Card Image Gallery The Lost Caverns of Ixalan releases November 17, 2023
