Here I was, reading the Shu Kurenai WIKI, and look what I saw:

"Shu is calm and patient, and prefers to be alone most of the time. He maintains a cool exterior in front of others, however underneath this lies a burning hot fighting spirit. He is quite standoffish towards people he doesn't know well, with Valt and Xander being exceptions. Because of this, he is sometimes seen as aloof and even as a 'spoiled brat', as described by Rantaro Kiyama  in the of the anime."

SpOiLeD bRaT!?

He is the last person in the Earth who is spoiled.

Rantaro, you need glasses.