Infinite Save-Scumming: Let's Save the World Together Again

[Rewind (the protagonist doesn’t rewind at first) + one heroine + battles]

(This is my first time trying this kind of story, so some parts might not be very well written.)

At last... we meet again.

Then let’s save this world, which was supposed to be destroyed, together.

Even if this journey may be doomed to fail.

This is the journey of a person forgotten by the world and a genius mage.