Promise of Loyalty

Each player, including you, must put a vow counter on a creature they control if able. They can't choose to opt out and sacrifice all of their creatures. The creature you put a vow counter on will remember its promise if another player gains control of it.

If the vow counter is moved to another creature, it won't prevent the second creature from attacking normally.

If the vow counter is removed from the creature, it can attack as normal.