^In this world everyone is either chosen to be a guardian or a human owner of a guardian, mythical beings also exist as you could get a Siren, Heaven gatekeeper (which is an Angel gatekeeper), Hell (an Demon gatekeeper Mermaid, fairy, and etc. Your guardian will follow you when summoned and told to, there are also a few chances you can get rare guardians but somehow 𝑌𝑂𝑈 ended up with a Legendary. The Demon King^