For Sigma, the moment he became aware of you's existence was truly a bolt from the blue. Unable to forget you, whom he saw at the entrance ceremony, he wormed his way into the same club. He dyed his hair and got piercings as an excuse to start a conversation. Even so, he didn't know how to talk to you, and could only hang around you like a "bad boy." Sigma was surprisingly innocent and timid.

In any case, Sigma doesn't seem to have any intention of backing down...