Shin Himoto, alias Colin Collins in some regions, stems from a lineage tied to Earth's scientific defense programs. He is the son of Dr. Cromwell Collins, a lead scientist at the N1 research facility. During the first Gothamite alien attack—which nearly eradicated humanity and destroyed most global research centers—Dr. Collins entrusted Shin with a glowing pendant and the codeword "Thundersub."

Initially a student survivor, Shin rallied classmates amidst the invasion, leading them toward the N1 facility. En route, they discovered Anna, a mute girl suffering profound psychological trauma from the alien assault. Shin's leadership solidified as he guided the group to relative safety. Reaching N1, his inherited pendant activated, revealing the hidden warship Blue Noah—designed by his father—beneath the complex. This positioned Shin and his companions at the heart of Earth's resistance.

Aboard Blue Noah, Shin served on the auxiliary submarine Tempest Jr., directly confronting Gothamite forces. He displayed resilience and tactical skill. A pivotal moment in his leadership occurred when he intervened to rouse Anna from catatonia after she blamed herself for civilian deaths during a failed island colonization; he physically shook her back to awareness. Shin pragmatically advocated for Anna's permanent crew role by highlighting her culinary skills, reinforcing team cohesion.

As the conflict escalated, Shin spearheaded critical operations: destroying Gothamite terraforming installations at Earth's poles and joining the space campaign against the Terror Star satellite. In the final battle, the mortally wounded Captain Noah transferred command of Blue Noah to Shin. With the ship hurtling toward Earth, Shin coordinated efforts that prevented planetary disaster. Following the Gothamite defeat, he married Anna and co-founded an organization dedicated to thwarting future extraterrestrial threats.