I always thought the whole Shinobu fanfic scene leaned too hard on the tragic backstory thing, you know? Like, she's grieving and closed off, and the popular approach is to have another character just wear down her walls through relentless kindness. It gets repetitive. The fics that stand out to me are the ones where the tension isn't just about cracking her open, but about her own agency in choosing to remain distant. Maybe she likes the solitude as a form of control after everything. That internal conflict—her own desire for connection warring with her need for self-preservation—creates a much sharper, more uncomfortable tension than any external love interest can provide.
There's this one fic set after the Mugen Train arc that absolutely gutted me. It wasn't a romance with anyone specific; it was just Shinobu and Tanjiro talking. The tension came from her trying to maintain her perfect, placid facade while he, with his unnerving empathy, kept accidentally brushing against the raw edges of her grief. He wasn't trying to fix her; his simple, genuine compassion was the thing that made her mask feel heaviest. That emotional tension was so quiet and devastating, built entirely on things left unsaid and a smile that kept threatening to crack.