I hate the harem-trope so much, as it is everywhere to destroy character development and to prevent the birth of good storylines...yeah. Go the yaoi route. This time just go for it and kill off the harem.
@ninjadoparana It does seem pretty strange the greatest hero of humans would be reborn into the demon royalty, though. So, it's possible he's Shin, after all. But who knows.
From what I've gathered from a spoiler thread in a forum, without reading the novel, there are many plot twists hidden already.
Many people enjoy this series for its heavy revelations, misdirecting and plot twists, so if you don't want to spoil the fun of getting surprises from those kinds of plot devices, please avoid reading the spoilers...
Summarized vague-trynabe major spoilers:
Kanon the hero, Reno the spirit, Melthea the creation goddess in chp1 were not in a formed hero party there to fight Anoth, they were gathered to cooperate with Anoth to create a world barrier thingy to split the world, they were on Anoth's side.
Actual enemies that I don't wanna reveal now because they still haven't debuted in manga created a magical destiny/rule thingy that push brainwashed humans to destroy Anoth, Kanon the hero tried to stop it with Anoth's subordinates. The demon emperors were brainwashed willingly as part of the plan, and other subordinates from 2000 years ago went hiding. Avos is a fake identity created as part of the plan, not a real being for now in the manga. Kanon was killed by enemies, reincarnated into Ray and pretends to be reincarnated Shin to approach and help Anoth, because real Shin didn't reincarnate.
Real Shin didn't reincarnate, he stayed with and married a debuted character, witnessed by Anoth and his gang through time travel, Shin's story is a whole complicated arc not really relevant at this point in manga.
Most characters surrounding Anoth are not simple, the twins are reincarnated beings too, Anoth's parents and sister are important and not as simple as they seem too, Anoth's character isn't fully explored yet too.
The later the story gets, the more complicated it gets, involving divine beings, world creations, collective divine consciousness, the universe with multi-layer worlds of different civilizations, origins and stuff. The 'Misfit' in the title isn't just about Anoth being a misfit in the academy, but a misfit in the world (at least the current world) too. However, with the pace the manga going, it'll probably take quite some time to reach that point I guess, so anyone who's invested enough may be better off with finding a way to read its novel.
P.S.: Idk anything else or how accurate these spoilers are because I don't read the novel, all the info I got are from a Chinese forum, so I can't confirm or answer any question not revealed in the manga so far, please take it or leave it.