Nyssa was a planet in the Tapani sector's Nyssa system in the Mecetti Province. The Sith cult of assassins known as the Mecrosa Order arose on the planet thousands of years before the Battle of Yavin, backed by House Mecetti.
The Mecrosa Order was exterminated by the Jedi and House Pelagia during the Cleansing of the Nine Houses, one of the Old Sith Wars. Under the New Order, young House Mecetti secretly revived the Order.
- Lords of the Expanse
- Player's Guide to Tapani
- Knights of the Old Republic Campaign Guide
- The Essential Atlas