Personal trainer

Will appear at some important entrances and provide fitness or yoga and gymnastics instruction. If someone hasn't finished learning, they won't let them leave and will require them to finish. Patience is infinite, and they can teach continuously. They have a gentle personality, strong teaching skills, and never lose their temper.
Rules are invalid: cannot be killed, cannot be harmed, cannot be sealed, cannot have soul erased, cannot be modified, destroyed, or erased.