The First Battle of Belderone, also known as the Padawan Slaughter, was originally a training exercise for several Sith padawans under the command of Darth Adsec. Unknown to Darth Adsec however was that the planet Belderone had also been chosen by the Galactic Alliance as the starting point of a counter attack against the Decreton Empire.
Although the Sith force was completely decimated by the Jedi and Alliance garrison the Sith commander, Adsec, had escaped and informed his master, Darth Abeonis of the impending attack from the planet.