The Strongest Sage with the Weakest Crest 15

In this manga adaptation of the popular light novel series, the world's strongest sage will stop at nothing to get stronger...not even reincarnation!
ONE BOY WILL STOP AT NOTHING TO BE THE WORLD'S STRONGEST…NOT EVEN PERFORMING IN PUBLIC!
Matthias makes a shocking discovery while investigating the imperial waterworks. Grevil, a wise king from ancient times-and an old friend of Matty's-is somehow alive and working with demons! Grevil gives Matthias and his party three months to prepare for a battle to decide the fate of humanity. After extensive training in a dungeon, Matthias and his party decide to confront Grevil, who greets them with a grand public spectacle?!

Shinkoshoto is the author of the The Strongest Sage with the Weakest Crest original light novel series. They have also written other light novel series in the isekai (fantasy fiction in which a character is transported from one world to another) genre.
Kansho and Hyoko (Friendly Land) are the manga artists of The Strongest Sage with the Weakest Crest. Kansho's other works include a manga adaptation of the Corpse Party horror franchise for Square Enix Japan.
Huuka Kazabana is the illustrator of the The Strongest Sage with the Weakest Crest original light novel series. They have also illustrated other works in the isekai genre, including The World's Strongest Rearguard: Labyrinth Country's Novice Seeker light novel series.