Kawasaki Kazusa (川崎和沙 in Japanese, 川崎和纱 in Chinese source) was a Japanese girl born in 2014, who was the first recorded ELID immunosome.
Kazusa was exposed to collapse radiation the day of the Beilan Island Incident, but only fell into a temporary coma instead of transforming into an ELID Infected. Her body had entirely adapted to live with radiations, but could no longer sustain itself without it.
The lone survivor of the immediate aftermath, she survived as a scavenger before being found by a UNRA scout team who brought her back to the Nagoya Japanese Self-Defense Force Recon Base in the local Protected Zone. Kazusa's immunity to Collapse radiation became known and some survivors saw her as a holy maiden who could protect them from infection, while others saw the 16-years old girl as a source of divine calamity. After the Japanese government abandoned all survivors south of Hokkaido on 24 May 2030, the latter faction tried to kill her, forcing the JSDF personnel protecting her out of the Nagoya Protected Zone and into the radiation zone.
When Raeder Rossartre in Tokyo learned about Kazusa, he made way to Nagoya with UNRA staff members and JSDF volunteers to protect her and study her immunity. Rossartre's team found Kazusa as the last survivor of the group that fled into the mountains of Shizuoka, and brought her back to the JSDF Camp Mishuku in the Tokyo Protected Zone. Kazusa agreed to become a test subject for the sake of finding a cure to ELID, and Rossartre arranged her extraction from Japan with Mikhail Tsvigun. However, Kazusa's existence was leaked to the Tokyo rioters by a traitor among the JSDF, and Camp Mishuku came under attack. On 19 June 2030, Kazusa was killed by a stray bullet while fleeing the Tokyo Protected Zone. Using a Weight Bearing assisted suit to carry her body, Rossartre reached Sado Island, where they were picked up by a Russian nuclear submarine and brought to Moscow by the Bolshevik resurgence faction.
Kazusa's body was designated Delta III by the Russians and autopsied, but the nature of her adaptation made her unsuited to the development of a cure to ELID.