Ren Tsukimi/Plot

Background
Tsukimi was childhood friends with Tachikawa, and mentored him in tactics. She joined Border during its debut.

Introduction Arc
Ren is first heard when Miwa Unit investigates the site of Yūma's battle with the Bamster. Miwa asks which unit defeated it, while Yoneya is impressed with the result of the battle, and Ren says they were the first unit to get there.

Large-Scale Invasion Arc
Ren is first seen when the Izumi and the Snipers team up to battle Hairein. After Narasaka manages to shoot Hairein, Iizumi shoots him with Asteroid to distract him. Ren then says Izumi is going to lower Hairein's guard, and tells the Sniper team to prepare to attack Hairein. After Kodera asks Tōma to stop playing around and Tōma tells Kodera to shut up, she tells Tōma she doesn't care as long as he hits the target.