Mizuki Segawa

Mizuki before the events of the Guyver series had a crush on Agito Makashima as he is dark, handsome and mysterious. For some time she was the secret crush of Sho's, but he was too shy and afraid to reveal his true feeling to her. Tetsuro, her older brother, always knew about Sho's feeling towards her and has said to Sho on many occasions that he approved if Sho could get up the courage to ask her out.

Mizuki Segawa

For a time she was actually unaware of the extent of how close she was to various more dark and devious plots. Even after Sho had activated the alien armor did she not fully understand the entire plot against her and the world. At one point she was kidnapped by Zerbebuth as bait for Sho to reveal himself but she was saved by an mystery armored figure called Guyver III.

It was not much later into the series after having been on the run from Chronos did Mizuki start to have feelings for Sho. Although having no superpowers of her own she has on many occasions been the push that Sho has needed to continue to battles against Chronos. During the period where show could not bio-boost due to the armor killing his father it was Mizuki being in danger that forced Sho to trust the armor again. Also it has been speculated that after the group's defeat at Relic's Point it was Sho's desire to protect humanity and Mizuki that caused the alien ship to protect the Guyvers and create the powerful Guyver Gigantic.