Strongest Sage With The Weakest Crest (Manga) Vol 17

After infiltrating the secret lab of the Unmoor brothers, Matthias and the gang wreak havoc on the mad scientists and ruin their careful plans to utilize the power of the Devastar! The older Unmoor brother reveals critical information about the Devastar, leading Matthias to confront a horde of powerful monsters protecting the Devastar. Matty's only chance of victory is to do the unthinkable and resurrect his past self! Square Enix Manga
(W) Shinkoshoto (A) Kansho & Hyoko, Huuka Kazabana