This is my comment from Manga updates, but you can't respond to comments there, plus it's pretty dead conversation wise.
This is by far one of the most overrated series out there.
Okay lol, let's brake this down. I'll start with the "romance", which is the part I found the most funny.
The romance as well as the rest of story is forced by a ridiculous amount. Yuuhi get's a harem for the sole reason that he is the main character.
Here are the girls' reasons for liking him.
Samidare: She met him as a little kid, and he tried to save her from.... nothing. She was never in danger, so all he did was look dumb.
Hakudou: He saved her from a golem, so by that logic shouldn't she be in love with like half of the cast?
Anima: He barely won a fist fight and then started yelling. She's an omnipotent god like being who's lived for an extremely long time and she falls for him because of something generic like that? Please.
Fourth random chicks who's name I forget: He picked up a cat. That's a logical reason to love someone right?
As for the rest of the "romance" in the story; it's pretty lack luster. The author just paired everyone up in the last chapter for no reason at all. Even the dialog in the story says that no one knows why certain people ended up together. Some people ended up together even though they never said two words to each other through out the entire series.
Now don't get me wrong, The beginning of the series was disgustingly good, so much so that's it's actually surprising how bad it ended.
A few chapters after Shinonome dies the story starts plummeting at a 90° angle. Let me get this straight; as he dies he uses his wish to give all his martial arts skills to Yuuhi; who he just met and knows is planning to do something bad. So why would he use his dying wish to help him?
It only gets worse after that, but I'll skip to the end of the story.
What's the point of having Anti hero main characters if you know from basically the beginning that they where going to change? The second Yuuhi forgave his grandfather the story's outcome was set in stone.
Samidare does not use her wish to curse her terminal illness because she stubborn? She blames her family braking up on her illness so she choose not to get rid of it? 10/10 logic there lol.
This one I found hysterical. Okay so apparently Anima's giant robot can only activated by Yuuhi because she loves him. Even though she built it she can't start it?
The third to last battle in the story is ENTIRELY pointless. Samidare tries to destroy the earth and the other knight besides Yuuhi try to stop her. (because Yuuhi is still pretending to be on her side). Yuuhi starts to fight the two mythical beasts knights and overpowers them like it's nothing, then is like "JK lol nvm; I want to be the one to stop Samidare.". Why did he have to beat them up first, pretty sure he could have just told them and they would have been fine with it. The reason why he didn't do that? Because the author was still trying to pretend that we as the reads did not know Yuuhi was a "good" guy. Forced dramatic build up and and extra fight.
Oh and Samidare's powers are stronger than Anima's even though Anima gave the powers to her? huh?
There are a lot of other examples of stupid pointless things I could point out, but I'd just be ranting at that point.
tl;dr version: This story gives no logical reasons for anything that is relevant to the plot.