Don't be daft. You know I was talking about the age and power gap, not the species difference.
There's nothing wrong with a good monster girl romance.
If you're going to talk about power, you have to consider the setting. Within the setting, the dude's basically an adjunct who lives alone in a shitty apartment who everyone hates, thinks is a loser, and bullies because of it. He
was a rising star and hailed as a hero like 20 years ago, but something happened and now he's... not. The monstergirls, who are the focus here, are seen as powerful and interesting varieties of monsters. They're held in high regard and one coming to the school has caused it to be showered with gifts and grants, as people seek their favor.
There's a power imbalance here, but it's not really tipped towards him. The fact that the first one can just choose him as a teacher shows you how much power she has. As her teacher, he does have authority over her, but she actively sought that and considering the influence that gets thrown around to court her, she could likely have him dismissed on a word.
My critique was of the author, not the story. This is obviously a romance manga; we all know where it is going. The mere fact that someone considers "middle-aged teacher falling in love (/lust) with his adolescent student(s)" a good story to tell, that's the problem I was arguing against.
Here you reveal your problem: you're not actually engaging with the story as it is. You're engaging in a story you made up because you want to think the author sucks. They may! I know nothing about them! But 'falling in love with his adolescent students' isn't this story.
The core is easy to see: 20 years ago the dude threw away his shot at life to rescue monsters from some horrible experiment. Clearly nobody else cared about these beings, but he did. We don't know why he taught them or much of anything about what occurred, but he saved them and had contact with them. He never thought anything lustful about them at all, they were creatures that he saved and accepted as worthy of life. He doesn't say a thing to their "I wanna marry the teacher" stuff, which he probably took as children being enamored with an adult figure as well as, yknow, their literal hero.
Somehow those creatures grew up, became incredibly magically powerful, and are now coming to find him. They're adults, he's working at a university, and they were already some kind of grown when he rescued them, so chronologically they could be in their twenties at this point, who knows.
See, this isn't a student/teacher fantasy. This is a specific fantasy of doing something good and it coming back later to help you. It's not "my hot student" it's "okay so that talking octopus I saved 20 years ago can somehow turn into a hot girl and has come to find me."
I like older male/younger female age gap romances, and they're very hard to find outside of Shoujo/Jousei/Smut. The idea of someone who's given up on life and love being re-invigorated by the love of someone younger than them is a very fun and satisfying idea. But most of them are
very predatory, because the other fantasy is that of an older man sweeping in and lifting you into a life of luxury/adulthood. The inherent problematic nature of that doesn't really matter in that fantasy because
they're the
prey and like that.
You don't have to read it, you don't have to like it, but I think you're being unfair to the author and the manga.