Sixteenth Basket of Mantaos

Imagine being forced to live, after death, as incorporeal bodies trapped in a vast space of nothingness for thousands of years, with nothing to do but exchanging past memories with other cohabitants (read: weirdos).  Everybody wanted out, but there was no way to leave the Void... 
Until one day, a young man was finally summoned, as a powerful but reluctant mentor, by a bubbly and motivated but completely naive young girl. Baiyi, finally out of the Void, was the only one who could save all of the other 32 souls from their prison and his summoner might just be The Key to their freedom.
However, Baiyi had to use the techniques and abilities the other souls had taught him throughout the years, and together with his own extensive knowledge of anime and game tropes from his shady and dangerous past as an otaku, to face the biggest challenge of them all: training the clumsy young girl he was forced to partner up with… into a competent sorcerer!

EndlessFantasy Translation 

Why Did You Summon Me？

"I bet that you all can tell what happened afterward," Baiyi said. "These gods waged war against each other.

"Try to imagine the scale of this battle, which involved gods, who can all bend the Laws at will. What do you think would happen when such beings weaponized Laws — which the universe is founded on — against each other? Simple: tens of millions of years of progress were gone in a few seconds. In the mad scramble to wrest control of all reality, the gods used the Laws over and over again, and eventually, what remained was hardly recognizable. The universe's foundation had been badly damaged; this, the Age of the Gods came to an end. That was a loss that could never be undone.

"I sifted through time and the Temporal Laws in a bid to uncover prehistoric memories, but all I could find were these little fragments, as almost everything else got destroyed in that war.

Hope