Another take on an OP MC in a fantasy world. The MC in this one did not reincarnate or transmigrate or time traveled either, he's just "immortal" (not literally) and very old so he just know a lot. Also, he's OP but has no talent, weird combo justified by his age.

Story-wise, thou it's early I'd say it's another hero trip, out to stop the Demon King that will be resurrecting soon, very original...there hasn't been much more than that so far.
My main gripe is with the MC, I find his character quite inconsistent. To start off, the MC changes like a pancake, he's an hermit, who doesn't care of what happens in the world yet one day into the journey and he starts walking the hero road. Also, he's supposed to have lost his empathy yet in the same chapter he says that he feels happy for another person's happiness, which is pretty much the definition of empathy, not to mention he goes out of his way to help people. Then he says he's loosing his emotions which makes less sense, he gets angry, relieved, irritated and so on all the time. Not to mention that after 5000 years I would expect him to be somewhat wise, what kind of idiot would tell someone he's an immortal off the bat? If there are no bad consequences for this it will be purely out of luck or the simple will of the writer. He also invents a magic that he himself labels as taboo yet has no qualm to teach it to another person... and an arch-mage at that. Furthermore, I know he has time to waste, but I find it hard to believe that both academy and Guild would waste talent making them start from lvl 0, going to the academy with his skills is paramount to a PhD. graduate going to kindergarten, and why does he need to go? he doesn't really care for others opinion and that the only "explanation" given. There are more but this is too long already.
Other chars are mostly ok, Pochi is funny at times and annoying at others and for some reason I keep imagiining her talking with the voice of Shiro of "Hoozuki no Reitetsu".
Comedy is... not to my taste, thou others seem to like it, at least it's not dumb and I did laugh a few times at the interactions of the MC and Pochi.
Last, art-style is good, a bit inconsistent at times but mostly detailed and with decent flow in the fight scenes, it's easy to understand how the action goes for the most part.

Overall, a decent fantasy with a kinda weird MC, has it's ups and downs but I think it gets more things right than wrong.