I used to occasionally lurk the /hhg/ thread on /trash/ as a guilty pleasure following the leaks. There was one major Alastor writer, and some of her shorter fics made him downright nasty. Though the longer ones did attempt to give him more emotional depth. The last one I read was about him as a young boy getting groomed, I presume leading to his psychopathy. It was weird thinly veiled fetish material, but interesting to hear her describe his violent thoughts and how he initially tried to suppress them. They were getting another Alastor fic as well about his childhood, but the updates were slow.