The bus driver has a special purpose in Rosario + Vampire, but still there are so many questionable aspects about him. Just how powerful is he? How can he drive in between the human and monster dimensions? How does he have the foresight of a god? And why is he so dang creepy?

Heartseed is a difficult anomaly to process. While the Kokoro Connect cast treat him as a villian, he is not necessarily a true villian. Just as he says, Heartseed is more of a "watcher" or a bystander in their affairs. He is very mysterious and hard to read, and can control anybody he wants to, so he can be very cold.

Kurasama is a true mysterious comedy-relief. Even though he often is used for his comedy purposes, just think of how little we know about Kurasama. He is like a steel-retention trap, especially since he says very little in the entire School Rumble series. Even his alleged lover, Tenma, often doesn't know enough about him.

Souma is pretty vague in all depictions, precisely because he hides all dirt on himself. This makes most aspects about himself a wild guess aside from him snooping on you.

Like, what is he? A possessed toy? A highly advanced sentinel? A robot? Whatever the boss is, Mr. Momoi is a very odd and vague character

Despite his role as the God of Causality, there is so much we don't know about Deus Ex Machina. Just how powerful is he? Why is he dying? How long has he existed? And why did he choose 12 complete messups of potential predecessors in his game? At least he seems to be morally stable, unlike one of his replacements.

From the brief horror anime title Another, Chibiki is another abnormal character. While his role as a librarian/archivist is pretty clear, the depths of his knowledge on the death cycle at the school and his general demeanor is very vague. He also seems to know when things are going to happen, which is pretty cool.

Now, you can diagree with me on this, but I think that Hachikuji has mysterious qualities. We know that she goes to elementary school and that she is continually searching for her home/mother. The problem with those things is that we are either never shown the background in the episodes (her school), or even, we are shown the background and we end up more confused than before. Her house is gone (sorry, spoilers), so why does she keep on searching? Where is she going? Does she just wander all day? But perhaps the biggest question that is not clear to me is this one: is she a wanderlust spirit, unconfined by things like time or school, or she is really just a regular schoolgirl, who really is totally lost? Her character, besides being a cute loli, perplexes me sometimes.

Oshino is legitimately vague. Though he has a long history, there are countless questions in the narrative of the -gatari series on his existence and who he is. He pops up out of nowhere, without explanation, in Kizumonogari. He is not strictly speaking just an exorcist, a channeler, or a oddity-killer. He is a self-described "middleman", an advisor and mediator to the rest of the cast. Then after Monogatari, he disappears just as oddly as he arrived. Oshino is a great character, but we know not very much about him.

Not much is explained behind his character, and a lot of details are left out, like his relationship with the Prez, or why he is looking for a New World.