Because you like Kallen Stadtfeld in Code Geass

The vampire that killed Zero Kiryu's family also infected him, and he starts to crave blood, much to his horror. See them in Vampire Knight.

Beneath Yuji Sakai's meek exterior lies an exceptionally keen mind and a strong inner will. See them in Shakugan no Shana.

The witty Aku would be an ideal dinner guest, if he weren't a demon. See them in Samurai Jack.

Gou Matsuoka offers to help as manager of a swim team, believing that they're the only ones who can help her brother. See them in Free! Iwatobi Swim Club.

A laid-back wanderer, Ginko has an empathetic, open-minded worldview. See them in Mushishi.

While his twin tries to save lives, Millions Knives does the best to end them. See them in Trigun.

He's the great Black Star, and he's come to assassinate you. See them in Soul Eater.

After several hundred years of shutting himself out from the rest of the world, Japan's not used to dealing with nations, See them in Axis Powers Hetalia.

If Anna Liebert could remember her past, maybe she would know who she is. See them in Monster (TV Show).

Everyone is just a chess piece, and Izaya Orihara is a master player. See them in Durarara!!.

Shana is a red-haired warrior with a black-and-white worldview. See them in Shakugan no Shana.

If there's power in being average, Mikado Ryugamine will find it and use it. See them in Durarara!!.