Nelvaan

"General Grievous has been spotted on a number of occasions traveling to planet Nelvaan deep in the Outer Rim Territories. I'm told he's there right now."

- Palpatine to Anakin Skywalker and Obi-Wan Kenobi Nelvaan was a planet in the Koobi system in the Savareen Sector of the Outer Rim. A frigid world, Nelvaan was home to the sentient Nelvaanian people. The Nelvaanians were considered primitive to many, as they lived in tribal villages, one of which was named "Rokrul."

History
In the year 19 BBY, Jedi Master Obi-Wan Kenobi and Jedi Knight Anakin Skywalker were sent to Nelvaan in search of the famous General Grievous, a leader in the Separatist Droid Army of the Confederacy. Upon arrival, the two Jedi and their clone troopers were attacked by a massive horax that killed all the clones before falling to the lightsaber blade of Skywalker. The two quickly realized they had interrupted the coming-of-age ritual of the son of Rokrul's Chieftain Tuzes-Adaz. Instead of having the Jedi killed on the spot, the chieftain brought them to the village to see Orvos, having remembered his prophesy regarding the two who would save them. After examining the Jedi, Orvos decided Skywalker was the prophesied Holt Kazed, or "Ghost Hand." He then sent Skywalker off to find what was ailing the Great Mother.

Skywalker followed instructions given to him by Orvos, leading him to the secret Techno Union facility. After seeing a vision of his future,[11] he discovered the Nelvaanian males being mutated and experimented on by the Skakoan scientists. He rescued the warriors and destroyed the base, killing the Skakoan workers out of rage. He then went on to return the men back to their women and children, who at first were hesitant to embrace them due to the massive mutations the men had undergone. With the siphon generator no longer sucking up thermal energy, the planet began to return to its normal temperature.