Sayo Kadoya

A version of Sayo Kadoya appears in Kamen Rider Heisei as an ally to her brother's girlfriend, Reika.

History
Unlike the "prime" Sayo, she doesn't possess a Stone of the Earth, which would allow her and her brother to access parallel worlds. As such, the duo lived blissfully unaware of other worlds until 7 years prior to the series, when the same shock that caused the "prime" Tsukasa to lose his memories caused their world's version of him to disappear as well. Sayo was heartbroken, but Reika promised that some day, he would return to them.

Personality
This version of Sayo is rather shy and introverted, with the only people she initally trusts being the Tomoe siblings. As the series goes on, she meets several new people-Reika's coworkers, Kai, and Arisu, among others.