Viras is a squidlike interstellar conqueror (and later intelligent kaiju eiga or gigantic monster) and from a distant star called Viras, from he derives his battle name. He came to earth in a space ship of ringed together spheres, each sphere the coloration of a bee, with the intention of conquering planet Earth, but he had one very large problem: the heroic giant turtle monster Gamera. Gamera easily stopped Viras' first scout ship before it even entered the atmosphere.
Observing Gamera's history from a distance (i.e. by watching stock footage from old Gamera movies), the conqueror learned both Gamera's considerable strengths and his only weakness: his protectiveness over human children. Viras then kidnapped two boy scouts, Jim and Mossau, and held them captive on his ship. With the boys in his possession on the ship, Viras was able to extort Gamera into wreaking destruction on Earth -- or he would kill the boys!
Unwisely, Viras allowed Jim and Mossau free reign over the ship and otherwise ignored them, assuming that as humans they were too primitive and unintelligent to interfere with his plans. The boys instead proved too much for Viras: they disrupted his evil plan by reversing some of his ship's controls, switching around some triangular control rods on the ship and thereby freeing Gamera from Viras's control.
Viras then revealed that the crew on his ship were actually human corpses being worn as disguises by other members of his species, each of whom were telepathically controlled by Viras, possibly with no individual personalities of their own. Viras destroyed the corpses, then absorbed his own crew -- in effect, murdering his own people without a second thought -- in order to transform from his 9 foot form into a form hundreds of feet tall, slightly larger even than Gamera.
In this form, Viras could clasp together his head flaps to form a sharp point that he could use like a spearhead. Gamera battled the giant Viras and was almost defeated when the monster impaled him in his stomach, but he flew high into the upper atmosphere, and in the end Viras could not withstand the low temperatures of the upper atmosphere and froze to death. Gamera then dropped the frozen Viras into the ocean, ensuring the conqueror's death.
It is unknown whether Viras had any successors back home, but it seems likely that, with Viras' death and with the apparent inability of his soldiers to operate outside his mental control, planets across the galaxy were at last freed with his death.