Guardian of Forever

The Guardian of Forever, also referred to as the Sentinel, was the name given to the creature that protected Forever, an underground city on the planet Alashan. The creature was the byproduct of an ancient complex within Forever. The power of the complex caused the creature's presence to give off an extremely large energy signal that could be detected at a distance, even by the sensors on an astromech droid. The creature and the complex had been seemingly created by an ancient race native to Alashan, whose technology and culture had been lost to time. For some unknown reason, the race had sealed their city's walls with a massive metal barrier, locking the Guardian and their ancient technology away from outsiders.

The Guardian possessed near-supernatural powers and strength. Among its arsenal was the ability to fire a concentrated superlaser, as well as the ability to modify its size and to teleport. After being released from its prison by curious Rebel archaeologists, the Guardian began to slaughter what it perceived as unwelcome intruders. Eventually, due to efforts of Rebels Luke Skywalker and Leia Organa and Imperials Wil'm Grau and Anarine, the ancient complex was smashed into disrepair, apparently killing the seemingly invincible monster.