I think it's going to be nearly impossible to accurately assume the Wolf until the series has reached an end. I'm sure that there will be little details that they didn't show the readers and somehow pieces together the conclusion at the end, but for now we can just use the logic we have. However, I do least suspect Rei. Mostly because we actually saw her dead body, unlike Eiji's. With those limited resources, it would be hard to fake a death like that.
Rabbitt Doubt is an intriguing series though, I've never really had one where I anticipate the next chapter so much. I'm also a huge psychology-buff, so the story is like finding gold in a field of coal. It's got a genuine and different plot, that doesn't need constant action to keep people reading. The story catches themselves all by itself. I really do think this is some work of genius, it's so original. Manga like this isn't seen very often, much less a good psychological one accompanied by beautiful artwork.
As for favorite character, undoing all killer-bias, I'd say Hajime. I don't care if he's the Wolf or not, but I completely fell for his character as soon as he was introduced. I do have a weakness for guys like that though, so it should have been pretty much expected. There's so much we don't know about him however, and he's got a talent for figuring things out quickly and coming up with a strategic plan.
Anywho, zethryvin brings up
excellent points about Haruka's suspicion. I had noticed a lot of those too, and at the beginning I simply thought she knew them personally. Then that safety layer was quickly gotten rid of. I've been really wary of her from the beginning, and Haruka does seem to know a lot more than she's letting on. Her more innocent expressions could purely be superb acting, as well as her fear. Or perhaps... (Spoilering this just in case, but it's only theories off the top of my head).
Spoiler Alert! Click to show or hide
Idea #1: Maybe Haruka started out as the Wolf, or she was assigned the role from someone else. Like, say she was implanted there as an inside source for the real Wolf. That would give her the access to the knowledge she has, because it's all factual tidbits and such. But that particularly answers how she knows so much about the other players. At the beginning she might have thought it was simply for a game, nothing too serious; and I assume that she most likely did not know who the Wolf was or who she'd been communicating with (After all, much of the game's planning is from cell phones). But when she saw that the Wolf was really series about killing, she got scared for her own life. That's when she started to suspect Yuu and became extremely cautious - because the Wolf wasn't going to side with her anymore. She knew that he/she would kill her. Hence, her manic and sudden change of personality and rationality. Where she wasn't expecting the game to turn out like this.
Idea #2: -Coming-
Offline 
