The Strongest Sage with the Weakest Crest manga volume 23 features story by Shinkoshoto and art by Liver Jam & Popo (Friendly Land).

After the fierce battle with the abominations, Matty and his friends make a stunning discovery. Hidden underground, someone has constructed a complex artifact that affects the entire world. Even more intriguing is the magic signature that identifies the artifact's creator as a being who possesses both human and demon energy! Despite the fact that this creator has been seemingly dormant for ages, Matty decides that confrontation is the best choice!