Isekai Tensei Shitara Aiken ga Saikyou ni Narimashita: Silver Fenrir to Ore ga Isekai Kurashi wo Hajimetara - THE COMIC

Ordinary salaryman Takumi works a grueling job, but he can get through it because he has Leo, his beloved puppy-sized Maltese, waiting for him at home. One day, Takumi wakes up in a fantasy world…and right in front of him is an enormous wolf! Wait, could this gigantic creature actually be the once-little Leo?! With the help of a mysterious new magic skill, Takumi will do his best in this world to make a better (and more relaxed) life for himself and his furry best friend!

(Source: Seven Seas Entertainment)