[serbian otaku #1]

A pretty decent novel I can't wait to see him meeting the others

As for OPness of the characters, i'll say this:

Spoiler:

Shen/Tomoe (blue haired girl) - Is a Supreme dragon, and is even called invincible. MC beat her in his first real fight. As of 19th chapter, she's level 1350 (the highest recorded before her was 920 by a woman that has a title dragon slayer. She has a human appearance because she made a ruling contract with Makoto (80:20). She also had an ability to create her own space, called Asora, but after the contract with Makoto, that ability evolved, and she now has her own pocket dimension. That's where Makoto is creating his mamono (monsters) city. It's basically a full blown world. albeit smaller.

Mio/Calamity Spider (black haired girl) - Is a calamity class monster. She's arguably stronger than Shen/Tomoe (she's also more battle oriented). Had trouble beating her since she was "starving", and was absorbing every one of his attacks. After he hit her with his last (and strongest attack), she became full, she jumped on him and started liking him. Afterwards she also made a ruling contract with him. As of 19th chapter, she has the highest recorded level of 1500 (because while Shen was sleeping, she was fighting/eating).

Makoto - Has an enormous amount of maryoku, so much that when he visited the first human village, they started attacking him out of fear. He later learned that that he releases as much maryoku as several demon lords. Also, because of the "gift" that that bug gave him, he understands magic chants and can modify them to suit his needs (he understands all mamono (monsters) languages. He's still level one.