[Edit]
The hero of the story, transferred to Jindai High school in order to protect Kaname Chidori. He was even assigned to the same class as her, thanks to the pre-arrangement made by Major Kalinin, Sousuke's senior officer in Mithril. He is 16 years old, same as Kaname.

Before joining Mithril, Sousuke called himself "Kashim," and fought as an Afghan guerrilla against the Soviets and others. Sousuke currently holds the rank of Sergeant in the SRT.

At first Sousuke piloted a Gernsback, but then switched to the newer Arbalest model. Sousuke's call sign is Urza 7.

The AS piloted by Sousuke. It is loaded with a Black Technology-based Lambda Driver, and judging from its external frame design is probably the successor to the M9 Gernsback.

The power that this mecha keeps hidden beneath the surface is simply unfathomable. Since the Arbalest was piloted by Sousuke in episode 6, it refuses to recognize anyone else but him as the pilot. This model still has numerous bugs to be worked out, however it is known the mech's Lambda Driver is functional.

A distinctive feature of this mecha is that its face resembles a ninja carrying a rolled-up scroll in its mouth.