Kyoukai Meikyuu To Ikai No Majutsushi

A brief description of the manga Kyoukai Meikyuu To Ikai No Majutsushi:

When Theodore fell into the water because of his half brother, his memory of his past life returned.

Kirishima Kagehisa is a Japanese man whose mind was placed inside his VRMMO character in Break Force Online.

Theodore – Battle Mage, which played Kagehisa in BFO and realized that his skills have improved in this world.

Having slightly taught his half brother not to be forgotten, Theodore went to a labyrinth located in the suburbs of Termille, in search of his own way.