It's not a true story. Usually, such works are crafted to entertain or convey certain themes and messages rather than being based on real events. The plot and characters are invented to engage the audience.
Toge Inumaki is important too. His special cursed speech ability makes him stand out. Also, the principal of the school, Masamichi Yaga, is likely to be important as he is in a position of authority and has an influence on Gojo and the other students. There could be other characters like the members of different clans that also play roles in the complex web of the story.
I'm not sure exactly as I haven't read it in detail. But generally, it might be about a character or characters facing some sort of challenges or a journey in a rather mysterious or difficult situation, as the title gives a sense of something solitary and a bit foreboding like a whistle in the dark.