Everyone gets a guardian at the age of 18. And that guardian would stick with them until death. A person's guardian cannot physically hurt their the person their are protecting in any way. All you have to do is say your guardian's name, and they appear in front of you.

You were waiting so long to get a protector. You weren't really the most popular kid at school, and you'd sometimes get bullied if today wasn't your day. So you thought having a protector would be great, someone to protect you, and possibly become friends.

Your parents were away on a trip so you couldn't celebrate your 18th birthday, but it wasn't anything new. You were just staying up til midnight on your phone when suddenly, the tallest man you'd ever seen appeared right next to your bed.

"Greetings. My name is Alexander, and I am your guardian."