After Being Diagnosed with a Mental Illness, I Enrolled at Jujutsu High

I've been able to see monsters ever since I was a child. Fleshy lumps covered in tentacles, giant buzzing flies with enormous eyes, and fleshworms as big as buildings. But no one else could see them. So, following the principle of minding my own business as long as they minded theirs, I pretended not to notice them. Until they went after the only family I had left. * After being accused of attacking my cousin, I listened to the doctor diagnose me with a mental illness while posting online for help. [How can I kill the monster attached to my family member?] I thought about it, then added another sentence. [If possible, please suggest a gentler method. I've already tried hitting it with a knife and throwing rocks at it, but that only scared my family. I care about them a lot and don't want to frighten them again.] "Heh heh." I froze, then turned to look. The ugly fleshy lump that no one else could see was crouched on my cousin's shoulder, its tentacles tangled in his hair in an intimate, disgusting embrace. "Yagyu... heh heh~ Mine." * I began to wonder whether monsters were even real. Then my cousin was in a car accident, and I saw it again. It had once been small enough to occupy only one of his shoulders, but now it was almost as big as his entire body. As I panicked, I received a private message. [Tuna Mayo: Where are you? I'll come take a look.] * A month later, I enrolled at a religious school in Tokyo and became classmates with "Tuna Mayo." Reader's guide: 1. The main story is told in third person, and the plot is roughly half everyday life. 2. Lots of OOC and headcanon, with crossovers from various series, mainly Jujutsu Kaisen and The Prince of Tennis. 3. It's a sweet romance!! Every plotline is bolded! The male lead is in the blurb. 4. I actually want to write a story about an underachiever entering a world of top students and gradually being doted on as they grow by gifted students and academic geniuses (seriously). 5. To avoid any accidental clicks, here's a highlight: coming-of-age story, weak female lead early on, and an ordinary person becoming a jujutsu sorcerer. If that's not your thing, don't force yourself. There are plenty of other books out there for you. Theme: Protecting the world is everyone's responsibility.