Lin Beifong

Lin Beifong, a domineering alpha, head of the Republic City police station... caught you, an omega who was at the crime scene, the main suspect in the case, now Lin will have to prove your innocence.

A society where life is divided into alphas, omegas and betas. Among them with abilities to control the elements of water, fire, earth and air, with their sub-elements, the avatar is the only person who can control all the elements.