Homura Akemi is the dual protagonist in Puella Magi Madoka Magica. She acts as a sort of "villain" or "anti hero" in the main storyline, at least from the perspective of other characters. Leading her to be misunderstood, which isn't helped by her seemingly cold, distant demeanour.
Homura is an introspective, sensitive person, very introverted, and cares deeply about others such as her best friend Madoka Kaname who she's sworn to protect.