
At first the story is hard to understand because there's so many of names and other elements. As the story goes it become clearer.
So here's some synopsis that might help you guys understand it.
It started with the legend about demon that steals the mirror that was left to the humans after the immortals goes to heaven. But it turned out that the story told to the humans is wrong. Kangchul who was one of the four generals who stole the mirror told them that the human tricked them so that they can monopolize the mirror for themselves and sealed the demon underground. So Geusendeu (?) The other general told them to steal it and kept it inside their body or weapons. After that the demons live in the above ground.
Hojung who was one of the generals picked up the child after the situation is peaceful. And that child is the minister taeryung. Taeryung fall in love with Hojung. And hojung just noticed that taeryung is not human. He's half breed. And his parents was killed by the demons that come above ground. He felt guilty for some reason so decided to sealed the generals and give back the mirror to the human so that the sun will shine again.
In the present taeryung broke the seal and the general with its shard of the mirror broke free again. And that's our timeline.
I think that's the gist of it.

Sure this is a bit boring and the way the author told the story is not that good. I got bored reading it. But I like how the problem between the couple is very realistic. The conflict in this webtoon is very common and usually what happen in real life. So I have to give a thumbs up for that. Usually other webtoon will just have lovey dovey moment. Or third wheel and etc. If only the plot is not rushing this will be very good.

Sure the MC looks someone who wrecked all of this. But he didn't EXPECT that his only wish can be granted in an unimaginable way. Going back to the past? Supernatural power? Surely if you're a normal person the first thing you felt is CONFUSION. You don't know what to do, what is right, what you have to do, what will happen if you change the future. So it's very NORMAL that the MC got so desperate and UNINTENTIONALLY make the people around him suffer more. UNINTENTIONALLY make the matters more complicated. You guys must know that in the original future he was READY to give up his love for Chance. Although in the end he was still wishing for his own happiness. Hey, is there someone who doesn't want to be happy? It's NORMAL to wish that you want to be happy. And it's very normal for a human being to WISH something. Why are you guys blaming him? Why are you blaming the natural reaction of a human being when faced with an unimaginable situation like that? Try putting your shoes in Henry's situation. He was afraid, he was confused, he was just being "normal", he doesn't know what's wrong and what's right. He is just trying to fix everything! Because he was afraid if he changes his behavior right now, it will lead to an unforeseen future. And does this unforeseen future is guaranteed to be a happy ending for all the people connected to it?
When you have a choice between a future that you already know and an unforeseen future with some risks you didn't know, what will you choose? It's natural for human to not want to leave their comfort zone. To not take any risk. So once again, why are you guys blaming MC who is much more "Normal"?

If it's blurry you should use avast private browser or some other browser available in your country until you find one that isn't blurry. Because it works fine in my phone and tab. I use long screenshot to make it easier for me.
Because I once read something in mangago and it's blurry I change my browser and it was fine. So try this method.
Is this harem? Like any other isekai manga where the male MC surrounded by many female and just a few unimportant male friend. And if the romance is too strong I'll have to drop this... Please help
Nope. Already read the latest chapter and there is no romance so far
How about the girls? Is it much? I read 6-7 chapter but all the new characters is girl. That friend of his looks like an unimportant character.
No, I think. A few girls appear but MC just interested in books.
Haha, I’m way too opposite. I hate harem lol