Hey there! So, I've looked through the usual tags for some good UnSub!Reid fics, and while some of them are quite good, they aren't exactly what I'm looking for, per se.
The two I've liked most so far are buffyaddict13's "Hopeless Son" and its sequels (Liked that one so much that I'm making a comic for it lol). I jove most of her stories, and I love the way she actually SHOWS how Reid breaks down. This isn't quite what I'm looking for, though, since Reid isn't exactly a serial killer. He murders, a couple of times, but not because he exactly likes it.
The other one I forget how I found it, but it's "A Terrible Liar" by wolfinred (clare_dragonfly). I LOVED this one! I'm really looking for fics like this one. Reid as a sadistic serial killer, right in front of the team's eyes. He's not -totally- delusional, he can still think rationally, but he kills anyway, etc. etc.
Thanks in advance~!