The Strongest Sage with the Weakest Crest manga volume 13 features story by Shinkoshoto and art by Liver Jam & Popo (Friendly Land).

After a lot of trouble, Matthias was finally able to use his ancient magic device to track down the demon mastermind behind all the schemes disrupting humankind. Normally, this would be the point when Matty goes and slays the demon, but this particular demon is not so easily slain. Zaridias is in a league of his own in terms of power and he’s ready to take a big swing at Matthias!