Age: 18 Unit: R-1 Rank: Second Lieutenant A psychodriver and a typical robot otaku. He is a bright, friendly young man who gets along well with others, though he has a habit of turning everyone around him into mecha otakus by introducing them to robot anime. His naming sense for special moves is notoriously bad. His nickname is Ryu. His R-1 combines with Rai's R-2 and Aya's R-3 to form the SRX.

Age: 19 Unit: R-2 Rank: Second Lieutenant A son of the prestigious Branstein military family, he possesses a generally cool and composed personality. Due to a past accident, his left hand has been replaced with a prosthetic. He and Ryusei became close after a period of constant bickering. His older brother, Elzam V. Branstein, is the captain of the Kurogane. His nickname is Rai.

Age: 21 Unit: R-3 Rank: Captain Mai Kobayashi's older sister. Aya is also a psychodriver. She was previously in a relationship with her superior, Ingram Prisken, and has been quite devastated since his death. Her usual personality is refreshing and straightforward.

Age: Mid-20s Unit: R-GUN Powered Rank: Unknown Aya's younger sister, who carries the burden of her past actions as Levi Tora during the L5 Campaign. While she has a gentle nature, she has become much more timid. Mai is also a psychodriver and harbors feelings for Ryusei. Her unit, the R-GUN Powered, becomes a weapon for the SRX to fire the so-called HTB Cannon (Tenjou Tenga Ichigeki Hissatsu-hou).

Age: 20s Unit: R-GUN Leader of the SRX Team Compared to her past self, she expresses joy and sorrow more frequently, showing a more human side. She also has moments where she lets her guard down and acts surprisingly goofy.