Gargantua

Defender, reach
At the beginning of your endstep, if you control
a land card named 4th Floor: Underground Lake
or you control an Ainz Ooal Gown planeswalker
transform Gargantua.
Not one of the Custom NPCs made in the Great Tomb
of Nazarick, but a part of the game system. The guild
members gave Gargantua the position as one of the
Floor Guardians in their dungeon.