Board Thread:Questions and Answers/@comment-38810345-20200611111726/@comment-10330822-20200611125231

Originally, his level is 1. When Satou uses the Meteor Shower icon it goes up to 310 after he kills everything in Dragon God Valley.

It then goes to 311 after he defeats Dog-Head with Meteor Shower, and becomes 312 after his fight with the Offshoot of the Demon God in his battle over the Royal Capital.

He goes to 313 after testing his artificial orbital spirit cannons on the Outsiders, then 328 after using his orbital cannons on Demon God's purple towers.

Lastly, he achieves 3100 after using Meteor Shower on the demons of the Underworld, because they come in such massive number and Satou gets an EXP boost because he combo kills them all with his Meteor Shower.

There you go, full level-up timeline.