This is kindergarten-level plotting IMO.
Only bringing up the guy when he's going to be important and then speed-running the development - very much as if the author made him up just in the last few chapters - have him make the MC look bad, then quickly reveal that no, he's actually a villain. And not only a villain, but an over-the-top villain complete with mad laughter. And not only that, but all the signs say he's going to be an easily defeated villain.
Man, this whole subplot could be cut away and nothing of value would have been lost.
I'm losing faith in the author...