"He never talks, just grunts."-Yin to Mina
Brock Troy, or known by his messier code BK-203, or "Brick".
He is a contractor who works with Hei, and works for the Maghrib Lift corporation as an enforcer, he has superhuman strength gained by wearing a power suit and his contractor ability to control his and others Volume and Mass. Its noted he never speaks, often communicates through actions, Yin seems to understand him better than even Hei can, as seen in ep 4. after smashing Misaki through a wall, Yin calmed him down using her sector and voice.
Brock has been noted to be very caring of Yin, protecting her from bullets and destroying a bus, when it went a wall.
Brock, has been noted to be very calm, and cool under fire, he does get very angry easily. Due to his abilities, his peers try to calm him down, though its difficult since he can't speak. Brock however is very loyal, and will do anything to protect his friends.
Brock, was believed to have been born in China, though the exact date and location are unknown, however like Hei he has Chinese citizenship, he probably was from the same are as Hei and Bai.