@4fliction It's ID - The Greatest Fusion Fantasy. Yes, that is the proper title. You can find it by clicking on the artist's name of this one, it's the only other listed work by him.
ID has a refreshing mix of over-powered "Isekai" protag (it was before the SAO boom to the genre) with lovable dorks as side characters and world building we sadly never got the full pay-off for.
Because it was axed at some point. I think because the publisher went bankrupt? Don't quote me on that. It ended together with The Sword of the Emperor, although it listed as "complete" on here.
I recall too well how chaotic it suddenly got with massive jumps only to get the story over with at the end.
But this is about ID. Which I can only recommend. Even with how "overpowered" ID is, he is still very much challenged and by far not unbeatable. Even some of the antagonists are a quite likeable. I still like to give it a read every now and again, just to remember the times of when I was still new to reading manga online.