
After reading 18 chapters, I arrived at two things:
First, Eunha is doing what he did in the past; testing his older brother. That is why he appears to be somewhat pitiful in front of him.
Second, Eunha has some kind of illness or plan on unal*ving himself after accomplishing his 5 wishes from his older brother.

I reckon Theo will soon use his remaining strength, magic, and resources to send Umehiko and Momo back to their own world. And that's because he loves him too much to the point of sacrificing himself and letting him go. He also might give up and abandon his wish of becoming a human just to prioritize Umehiko and his sister's well-being. I can't, Theodore's character development gone from 0 to 180, indeed.

The ending is not what I expected, but it plausible, given that there's a lot of factors needs to be considered, especially when the author will make Dohyeok–Siwoo couple the end game. There's the fact that Siwoo deeply cares about Suha, and treats and sees him as a younger brother, and the fact that Dohyeok is the very person who makes that little brother he cares about suffer physically, emotionally, and psychology again and again. So I really understand why they did not pursue, at least for now, the D–S couple. But I at least expect them to give Do hyeok's character growth in various aspect; moved on and go about his new found life. He's trash in and out but he also suffered: he got graped, remember? And although that doesn't justify his past and current trash behavior and actions, I want his character to process that and heal, so that he can finally apologize to those people that he wronged and ask for their forgiveness (whether they forgive him or not). But as it stands, and if this is really the end, then I guess that author failed to give justice to their side characters stories, so I reall hope that there's more to this that will really give closure to all.

I agree with people who were saying that this deserves a live action/movie/anime adaptation. The story was well written and the characters were well designed: from their personalities, views, actions, and their stories. This manga deserves to be known and be appreciated by the world. Give us some moreeeeeeeeee, I beg of you.
It's sooooo wrong to end this hereeeeeeeeeeee. Noooooooo, give us mooooooore