A Semblance is a manifestation of a person's Aura-- their soul, basically. It's unique to most individuals, but mine is hereditary.

[She smiles at the compliment, however. It's nice when her skills are appreciated.]

I learn it because [I had to.] it gives a major advantage when fighting against monsters. When using your Semblance is as natural as breathing, its one less thing you have to think about on the battlefield.