Derreth Berylhelm

: Derreth Berylhelm can be your commander. All lands are mountains in addition to their other types.
+1: Create three 1/1 red Dwarf creature tokens with mountainwalk.
0: Until end of turn, Derreth Berylhelm becomes a 5/5 Dwarf Warrior creature with Indestructible and Mountainwalk.