Agito is the adopted son of the head of Chronos Japan. He also goes to the same school as Sho and Tetsuro and Mizuki adores him. However he is not all that he seems and turns out to be Guyver III
Agito is the adopted son of the head of Chronos Japan, Genzo Makishima. Years ago his parents company was bankrupted by Genzo and after they died he was adopted by Makishima. Agito was one of his schools top students and would serve as Genzo's personal assistant when he was old enough. Unknown to Genzo however, Agito grew up hating the man that killed his parent. The young Makishima masked his true feeling from his adopted father and the corporation that he worked for.
Using his father's access to Chronos, Agito learned about the existence of the Guyver Units. He convinced an incomplete Zoanoid to steal the units and that he could be unprocessed (a lie). However before the hand off could be complete the units were intercepted by Chronos. Due to an explosion two of the units were lost but Agito was about to recover one (which would be known as Unit 3). The first was found by Agito's classmate, Sho Fukamachi and was inadvertently activated by him. The second unit was recovered by Chronos (but was damaged). Agito activated his unit and keeping an eye on Fukamachi, quickly learned as much as he could about the unit and its abilities.
In Guyver: Out of Control, Guyver III makes a cameo at the end but Agito is never shown out of the armor.