Man, I need books that actually make me believe the serial killer could be a romantic lead without it feeling like a complete fantasy. Too many just slap a 'psycho' label on a guy who's basically a grumpy CEO with a knife collection. I want the real, ugly psychology there, but I also need the emotional pull to be earned.
A.L. Jackson's 'Fallen Crest' series? Not exactly serial killer, but the male lead has that dangerous, obsessive edge that flirts with the trope. It’s more contemporary dark romance, but the emotional torment feels real. For a purer blend, maybe Penelope Douglas? Her 'Devil's Night' books have characters committing brutal acts, but the core is their twisted loyalty and history. It’s less about the murders and more about the codependent trauma bond, which is its own kind of depth.
Truthfully, the best 'blend' I've found often isn't in pure romance shelving. Try some dark romantic suspense from authors like Karen Rose. The thriller plot drives the book, and the romance develops slowly amidst the chaos, making the connection feel hard-won and significant.