Hairein

He is Neighbor from Aftokrator, and the head of House Veltiston. He is a Black Trigger user and the captain of the group that invaded Earth.

Hairein is a tall neighbor with long, messy blue hair and neat blue eyes. Like all other Aftokrator Neighbors, he has two horns on his head. In the anime, he is portrayed with light blue-gray hair.
According to Ashihara sensei's comment, his image of design is dragon.

Hairein has a careful and calculating personality, and is also shown to be a good strategist. He seems to be intent on fulfilling his group's goal. Despite this, he is a pacifist and fears Mira due to her sadistic personality. He appears to have a sense of ethics as he chose tactics which divided enemy forces and concentrated on capturing C-rank agents only.

(Source: World Trigger Wikia)