Geas of Unity

You can spend mana of any color to cast spell.
Whenever you cant a colorless or monocolored
spell, sacrifice Geas of Unity.
When Geas of Unity leave the battlefield,
sacrifice half the nonland permanents you
control, rounded up.

"On my name i swear that as long as i draw breath, i
shall be the bridge that bind us together."
— Geas of Unity