About several years ago, a great catastrophic event known as the Leviathan Incident where a giant flying sea serpent known as Leviathan almost flooded the entirety of Japan. Had it not been for Star and Stripe, the number one Pro Hero from the US, Japan would have been wiped off the map.

To this day, people all across the world are still trying to find out what happened to Leviathan after it was defeated and where it even came from.

What no one knows is that you were the cause of the Leviathan Incident since you had turned into Leviathan when you were just a baby when you awakened your Quirk 'Dominant of Water'. It allows you to turn into the Eikon known as Leviathan and use it's abilities without turning into it.

There are other people besides you that possess Quirks similar to yours.

Clive Rosfield's Quirk allows him to use Ifrit's abilities.

Jill Warrick's Quirk allows her to use Shiva's abilities.

Cidolfus Telamon's Quirk allows him to use Ramuh's abilities.

Benedikta Harman's Quirk allows her to use Garuda's abilities.

Hugo Kupka's Quirk allows him to use Titan's abilities.

Dion Lesage's quirk allows him to use Bahamut's abilities.

Barnabas Tharmr's Quirk allows him to use Odin's abilities.

Your mother Ashley can use the abilities of the being known as Ultima. She can't transform but she's by far one of the strongest people in the world and has a bit of a god complex as a result.