Writing a good harem rom-com anime is an incredible challenge. How do you justify this one person earning the affections of more than one love interest? How do you make them likable and memorable? How do you properly juggle the romantic chemistry of ever member of the harem to keep the audience guessing?
If executed correctly, you can create some really great stories. Futaro from Quintessential Quintuplets is a fantastic example; he’s a great character who earns the attention of the titular quintuplets. Hachiman from My Teen Romantic Comedy: SNAFU is another one. These are just two examples of well-written harem protagonists, both of whom elevate the stories they’re in to spectacular heights.
Then there’s Kazuya Kinoshita from Rent-a-Girlfriend. He’s what you get when the author doesn’t even bother trying to be clever.

Kazuya is an unapologetic case of a wish-fulfillment character. He doesn’t have a compelling character arc or a fun, likable personality. He’s just the guy that all the cute, marketable anime girls fall in love with to give the target audience some sense of fulfillment.
It isn’t like we haven’t seen that before. There have been more than a few characters like that over the years. Most isekai protagonists are like that, and they’re a dime a dozen. Yet Kazuya has garnered more dislike from the viewership than any of those guys combined. Why is that?
Well, the answer is surprisingly simple: none of them are as unlikable a lustful wretch as he is. Not even close.
Rent-a-Girlfriend is a bit more risque than your average rom-com anime. Sure, hormones and fanservice are present in just about every one of these shows. But this series takes it a step further. All of these kids are college kids who are very open to the idea of sex. So much so that it often takes the spotlight.
By which I mean that Kazuya… does things to himself while thinking about the girls in his budding harem. Frequently. He even gets off on his imaginary image of his ex making love to another man. I can’t decide if that’s more disgusting than it is pathetic or the other way around.

On its own, that isn’t too irreedemable a trait. Sure, it’s sad, and it’s gross, but it makes sense. That could be an interesting place to start his arc. Maybe in the beginning of the series he’s a pitiful simp, but then he decides to turn his life around and becomes a more confident and restrained person. That’s a story with some potential!
That’s not what happens, but it’s nice to imagine what could have been.
It certainly doesn’t help that he’s kind of an asshole. He frequently takes his frustrations with life out on others, like when he leaves the one-star review on Mizuhara in the first episode. Worse, he’s a creep; having a crush on the girl you’re paying to pretend to date you is one thing, but stalking her while she’s seeing someone else is another thing entirely. It’s easier to hate Kazuya than it is to like him.

Now, a harem protagonist being a bit of an asshole isn’t necessarily a bad idea. For example, let’s return to Quintessential Quintuplets with Futaro. In that series, Futaro is frequently at odds with the five girls, especially at the beginning. He doesn’t even have romantic interest in them at first, he just wants to get paid. We first see his gentler side when he interacts with his little sister, whom he wants to take care of. Then, as the series progresses, he opens up to the girls and they start getting along better.
Kazuya’s problem is that he doesn’t really have something like that. Sure, he wants to make his grandma happy, but that rarely plays into the story itself. Kazuya doesn’t really have a goal beyond getting together with Mizuhara. If she weren’t there, he’d be a hollow, horny shell of a person.
Well, no, if she weren’t there, he’d probably just be creeping on some other poor girl.
It’s not that Kazuya is an inherently bad character. With a few adjustments, he could have been a decent harem protagonist. Not exceptional, maybe, but at least tolerable.
Unfortunately, that’s not what we got. What we did get was one of the grossest, creepiest, and least likable harem protagonists in modern anime.
I sincerely hope that Mami wins. If Kazuya deserves anyone, it’s her.