My Isekai Life 18: I Gained a Second Character Class and Became the Strongest Sage in the World!

Yuji Sano was a normal guy working a soul-sucking nine-to-five job when he suddenly found himself transported to a fantasy world where he restarted his life as a Monster Tamer. After befriending the Slimes, Yuji is quickly able to gain a second character class, ranking up his stats and learning new skills as he encounters one surprise after another. While on a reconnaissance mission inside a creepy laboratory hidden in the middle of a wraith-infested forest, Yuji's Slimes are spotted by the facility's security system—the same one that wiped out all the researchers in the decimated laboratory as part of an extreme data-leak prevention policy! With the Slimes in the crosshairs of the facility's bloodthirsty security system, will Ancient Rhino make it in time to save them?!

Volume 18 of the My Isekai Life manga series by Huuka Kazabana.