I’ve been reading Dabi/Reader stuff for ages, and honestly a lot of lemons circle back to a few core setups. A huge one is the 'enemy to reluctant allies to lovers' arc, where the reader character is maybe a hero intern or a civilian who gets caught up in League business. The tension comes from that initial hostility—maybe they’re held somewhere, or forced to work together—slowly thawing into something else. The appeal is the rawness and the defiance of it all, two people from opposite sides finding a twisted kind of understanding in physicality.
Another theme I see constantly is hurt/comfort, but make it extremely dark. Dabi’s scars and chronic pain are central; the reader character is often a healer, a doctor, or just someone who isn’t repulsed by his appearance. The lemon scenes become a form of catharsis, where physical intimacy is the only way he can accept care or feel something other than pain. It’s less about pure fluff and more about exploring vulnerability through a very gritty, intense lens.
There’s also a subset of fics that play with power dynamics and corruption arcs. The reader starts out normal, maybe even idealistic, and Dabi deliberately draws them into his world. The lemon scenes chart that descent—initiation, manipulation, eventual embrace of chaos. It’s popular because it leans hard into his villain persona, offering a fantasy of being chosen and claimed by someone utterly unhinged yet magnetic. The settings are often grimy, like abandoned bars or safehouses, which adds to the aesthetic.