- Kamen Rider Den-O is a series about time travel. In an alternate timeline where she never met her astronomy-loving boyfriend, the main character's sister gives her cafe a flower theme, instead of an astral one. A character from the future is revealed to be her daughter. Her name? Hana, which means flower.
- Towards the end of Ore, Tanjou!, the DenLiner makes a sidetrip to the time when Ryotaro was born, allowing Ryotaro and his younger self to see his parents for the first time. Hana is also seen looking out the window as well... because it's her first time seeing her grandparents.
- Den-O's form when possessed by Sieg is the Wing Form, meaning he uses wings to attack. Sieg is a swan-themed Imagin. Swan wings can break human bone.
Fridge / Kamen Rider Den-O