Hiroshi Watari's Guest Appearance in Boukenger

Hiroshi Watari who played both Metal heroes Spielban and Sharivan (who are NOT each other in contrast to Kamen Riders Black and Black RX) also appeared in Boukenger (in a flashback) as Eiji Takaoka's father and thus explaining why Bouken Silver looks so "Metal Hero" despite the genre being frozen or probably done for as of this moment.

His character was that of the vampire hunter who unfortunately fell for a bouma and conceived a hanyo son in Eiji Takaoka who is considered a wandering violent demon by both Gai and Rei. His romance gone bad, he was inevitably killed by the Ashu before becoming Questers for his forbidden relationship.

Note: He is currently married to Jun Takanomaki and is retired.

Source: http://www.whosdatedwho.com/celebrities/couples/profile/jun-takanomaki-and-hiroshi-watari.htm