then its ryusei but I have more riders in this at least 4 and Ryusei's human name is Seiichi hikaru and seiichi is my japanese name i was give at birth by my grandmother who was from gunma ken japan
With a dragon, why not try the five animals of Kung Fu?
--
Kamen Rider Zerpens: evil Kamen Rider with monster form.
* Human form: Gyasa from Shinzo
* Rider form: A cross of Kamen Rider Ohja, Cobra (Kamen Rider movie), & "Guyver Zoanoid" (Guyver 2) with elements from the Green Goblin armor.
--
Kamen Rider Taiga: Ryuusei's rival.
* Human name: Taiga Hikarikiba
--
Kamen Rider Grus: A Crane-themed rider.
Kamen Rider Pardo: A Leopard-temed Rider
Genbu - Black Turtle
Seiryuu - Blue Dragon
Byakko - White Tiger
Suzaku - Red Crane
Kouryuu - Gold Dragon
Alternately you can use the Chinese names but I don't remember them as well (I could find them but the Gold Dragon's name is nearly impossible to find).
------------
Sol Rider
Luna Rider
... I can't think of anymore names using this string. Sol is the name of our Sun, Luna is the moon (though thats a bit obvious).
------------
You could use the Japanese names of the constellations... the only one I know is Ryuuza which is the Draco constellation.