In Alternative, it's revealed that the brain Shirogane Takeru frequently saw was, in fact, the remains of his childhood friend, Kagami Sumika. As Alternative IV was never completed, she couldn’t be turned into the pilot of the Susano'o and humanity's strongest weapon in the war against the BETA, the 00 Unit. A humanoid supercomputer with unparalleled ESP capabilities, emulating the personality of Kagami Sumika, obsessed with killing all of the BETA that killed Takeru and her.
