Sechs

Sechs (German for "six") is one of the TUNED AR Series 2 combat androids. Formerly AR-6 and known in Japan as GR-6, he was created by the Ground Investigation Bureau (G.I.B.) to replace Alita as a TUNED agent. After the collapse of the G.I.B., AR-6 went on to challenge and kill all of his "sisters" save for Elf and Zwölf in an attempt to establish his own identity, changing his name to Sechs.

Unlike his sister unit AR-2, he is noteworthy in that he does not wish to replace Alita, but believes that in defeating her he earns the right to exist as himself. Although originally assigned female, Sechs currently inhabits a male body and has a masculine personality. He has expressed some disdain for his previous TUNED body. Sechs' rivalry with Alita was been largely sidelined during the Tenth Zenith of Things Tournament, during which he developed a new rivalry with Zekka. After his defeat by Zekka in the tournament, Sechs was instrumental in restoring order to Robo-Asyl. He subsequently joined the Stellar Nursery Society.

Sechs has a highly aggressive personality and greatly enjoys fighting. Following the fall of the Ground Investigation Bureau, Sechs, like the surviving TUNED AR Series 2 androids, began developing his own personality. This is possibly derived from the TUNED AR Series 2's original programming, which in turn was based on the destructive and nihilistic personality that Alita had developed during the decade that she spent as a TUNED agent. Following his defeat by Alita he began to question his own reason for existence, which has led him to ask Zazie and Zekka what their definition of a true warrior is.

Although being initially assigned female, Sechs transitioned with the acquisition of the Fizziroy Body, which is anatomically male. He has also developed a better sense of strategy and exhibited exponential personal and emotional growth during the Tenth Zenith of Things Tournament.