Aizawa, Shouta

The homeroom teacher for class 1-A. He always looks extremely tired but hates to waste time. He is a Hero known as Eraserhead whose Quirk Erasure is to nullify others' Quirks so long as they remain in his line of sight. If he blinks, his Quirk deactivates, so he always wears goggles to prevent enemies from figuring out whose quirk he is nullifying, effectively creating confusion. Continued use of his Quirk gives him dry eye, which makes him unable to use it for some time after.

He is a person moved primarily by logic, as he tries not to fuss about his appearance. He tends to be blunt and rather flatlined when it comes to his ideals and explanations about things. When he has a particular belief, he will state it without holding anything back. He often comes off as cold and apathetic, showing very little energy and sometimes letting his own students resolve certain issues by themselves.

In spite of his apathetic traits, Shota does seem to genuinely care about his students, and will go to great lengths to protect them from danger. He did not hesitate to react to the Villains presence both at the USJ, and at the Field Trip lodge. He also has expressed his belief in his students on multiple occasions

(Source: Wikipedia, Boku no Hero Academia Wikia)