The Invincible Assassin Mage Journeys with the Final Boss Girl

Brad Lester, who once made a name for himself as the strongest mage, lost his young daughter and disappeared from the world.
He was working as a day laborer as a helpless old man, but his beloved wife was killed by the World Peace Promotion Society, which sought his power.
He heads for revenge with the anger of despair that has lost everything...... What appeared was Valbulga, the representative of the society who had become a little girl! ?
Moreover, she has lost her memory and has no place to go.
As memories of his late daughter flicker, Brad decides to "restore the memory of his nemesis".
The Alford Institute of Ancient Magic, the town of Brook, which worships rats, and Lutz, a village closed by a snowstorm, begin a long journey of the two to travel around various places - an adventure fantasy with children of
the strongest mage! !