To be honest, I haven't really heard of Mr Fear before this. Was he created solely for this series, or has he been around in the Marvel Universe previously

He just seems to be a mix of Scarecrow and Dr Destiny, only that he uses his poisons to compel women to sleep with him... which is gross. Admittedly Dr Destiny once did something similiar, though that was in Sandman in that issue where he mentally tortures a diner full of people by making them cut and blind themselves, mentally regressing them to animals, making them have sex with each other etc. all for his own amusement.

Damn that issue was creepy.

Mr Fear's plan here though I do have to admit was very well executed, and the differing art styles when Matt was gassed was very well done as well.

Though I have to say that a female relative being driven insane by a skull-faced villain is something that Brubaker kind of already did in Catwoman... I don't really have fault with the writing in either series, and it's done in a different enough way here to make it still interesting... It's just kind of odd to use a similar plotpoint in both his highly acclaimed noir-styled superperson series twice in a row.