|Full Name||Chiba Toshikazu|
|Weapons & Equipments|
|Voiced By||Hidenobu Kiuchi (Anime)|
|Novel||Volume 6, Chapter 1|
|Anime||Episode 19, Yokohama Disturbance I|
Erika is Toshikazu's little half-sister. Despite Erika's antagonism with him, Toshikazu really cares for her and considers her a true member of the Chiba family. Because he considers Erika to be his cute little sister, he enjoys teasing and antagonizing her.
He is attracted to her and often cooperates with her.
The only interaction he had with Tatsuya was in Yokohama incident. They met while trying to stop the invading forces, but Tatsuya was presented as "the Special Officer Ooguro Ryuuya of the 101 Independent Magic-Equipped Battalion." When Tatsuya jumped from the building and flew away, it left him even more confused.