Toshiki Seto (瀬戸 利樹 Seto Toshiki) played Hiiro Kagami in Kamen Rider Ex-Aid.
- Seto has appeared in a movie called Strayer's Chronicle along with Shunya Shiraishi who portrayed Haruto Soma in Kamen Rider Wizard.
- Seto has an aversion to sweets, which he attributes to getting a nosebleed after eating too many chocolates as a child.
- Conversely, his character Hiiro appears to have a liking for sweet foodstuff such as desserts.
- Seto claims that his favorite Rider is Ouja of Kamen Rider Ryuki.