Ssi-ruuk

The Ssi-Ruuk are a saurian race that invaded from outside the known galaxy in the novel immediately following Return of the Jedi, The Truce at Bakura. They resemble dinosaurs and are covered with a thick scaly hide. Their skin is so thick that it can withstand blast shots with only minor burns to show for it. They have clawed hands and feet, strong hind legs and powerful tails. The Ssi-Ruuk also had a rigid caste system based on skin colour. Their caste system comprised of four main groups: blue, gold, red and green. Blue Ssi-ruuk are the politicians and leaders of Ssi-ruuvi society. Gold-scaled Ssi Ruuk served as the clergy while red-scaled Ssi-Ruuk were the military caste. The largest caste were the green scaled Ssi-Ruuk who were workers. There is also a related species, the P'w'eck that are only slaves.

This race relied on a technology called entechment that involved capturing the life-energy of beings and using them as power sources. Apparently contacted by the Emperor Palpatine through the Force, the Ssi-Ruuk came to the galaxy to trade some of their battle drones for slaves to entech. The Ssi-Ruuk had discovered that humans lasted the longest as batteries when the Emperor died. Stranded at the edge of the galaxy, they tried to invade and capture more beings for power. Early in their invasion, they had captured and brainwashed a Force-sensitive boy named Dev Sibwarra and used him to calm the subjects being enteched. Bakura was the Imperial world where the Ssi-Ruuk were stopped after the Rebellion sent a force to aid the planet. The Imperials and Rebels made a temporary truce to fight off the Ssi-Ruuk, who, upon being defeated mainly through the efforts of Jedi Knight Luke Skywalker departed and were not heard from again until the Yuuzhan Vong war.