Higa Takeru

Takeru Higa is the Chief Developer of the «Soul Translator.» He works under Kikuoka Seijirou in RATH, using «Underworld» as a means to create a Bottom-Up-AI, be nurturing a mass number of Artificial Fluctlights, in order to further Japan's military force.

He claims his reasoning for doing so was that a friend of his had gone and joined a war, only to die.

Versus
In this side story he talk with Kazuto before he enters the new Full Dive technology machine, and tells him about the ghost that other users of the machine has seen.