With its beloved sword — Hoshikirimaru — in hand, this alien swordsman roams the universe in search of an opponent stronger than itself.
Its skill is such that it can take down 100 aliens at once, and is revered across the universe as a legend who only needs nothing else but its sword.

Having heard rumors of Hunter Knight Tsurugi and wanting to challenge him, it rode to Earth on a comet.
As it was about to destroy CREW GUYS’s Silver Shark G in an attempt to draw out Tsurugi, Zamsher was stopped by Ultraman Mebius.
That’s when Tsurugi showed his true form: Ultraman Hikari.
Hikari appeared to be able to immediately break Hoshikirimaru in two, but told Zamsher that the sword had already broken during the battle against Mebius.
Zamsher admitted defeat and left Earth.

Zamsher would later return to Earth to help Mebius and Hikari defend Earth against Alien Empera, the Dark Space Emperor.
It sliced up the Impelaizer and fought the Space Emperor, but ultimately died protecting the humans.