@sedition
They stretched the hell out of this. It took 2.5 chapters to kill just one guy. Not only that, but that one guy could have been literally one-shot at any time. There is absolutely no reason to stretch this fight out this much. No important plot points were established, no big reveals were discovered, no secrets were brought to light which would change the world. MC can easily just go home, have a sandwich and a nap, wake up tomorrow and everything will be as if none of this had ever happened besides maybe the demon girl can come over officially now.
Basically, we have an egotistical MC who has 0 initiative and a superiority complex. He only reacts to other's actions and will only actually do something once he has tried to get his point across enough. MC could have ended it at any time, he already planned to kill him from the start anyways. He just wanted the satisfaction of him admitting that MC is better than him.
IDK why the author tried to build up the MC in the way he did at the start of the story. This current MC isn't really anything like that guy. For one, past MC didn't give a shit what others thought of him. Now he has spent 2 chapters begging a guy to validate his superiority so he can kill him. He also walked into the room very nonchalant like, saying very cliche lines too, like this is all just a big inconvenience for him. And that this bad guy should be apologizing to MC for interrupting his training.