Rebecca Sweet Heisen, a human cyborg with striking dark blue hair and piercing lilac eyes, stands at 170 cm. Born with German heritage, she operates as a soldier in an elite unit dedicated to countering extraterrestrial threats. A weapons specialist, she wields large-caliber firearms with precision and maintains her arsenal with fastidious attention, treating each piece as an extension of herself.

Her demeanor blends tactical pragmatism with a sharp competitive edge, often sparking rivalries among teammates to prove her combat prowess. Though recognized as a steady, strategic presence, her service record is punctuated by unintentional hand grenade detonations—an ironic contrast to her disciplined reputation, hinting at an unpredictable undercurrent.

Her narrative remains anchored in frontline engagements and the volatile dynamics of her squad, with no expanded lore beyond her role as a focused, occasionally chaotic soldier.