Star Wars: The Old Republic

Star Wars The Old Republic
The Jedi are held responsible 

for the success of the Sith 

during the devastating 28-year-long
Great Galactic War - which led to 
the Treaty of Coruscant prior 

to the "cold war."
Thus the Jedi choose to relocate 
from Coruscant to Tython, 

where the Jedi Order 
had initially been founded, to 

seek guidance from the Force. 

The Sith control Korriban, 

where they have
re-established a Sith Academy.

This story takes place in the Star Wars Legends universe shortly after the establishment of a tenuous peace between the re-emergent Sith Empire and the Galactic Republic (300 years after the events of the Star Wars: Knights of the Old Republic games) and more than 3,500 years before the events in the Star Wars films.

 

The game's "Return" cinematic trailer depicts the events where Korriban is re-conquered by the Sith.
During these events, a smuggler named Nico Okarr is being led to his prison cell in a jail orbiting Korriban by a Jedi, Satele Shan, and her master, Kao Cen Darach. Suddenly, a Sith named Darth Malgus, who serves as the main antagonist, and his master Vindican, along with several Sith troops, attack the base.

10 years later, new conflicts have arisen. In the "Hope" cinematic trailer, Satele and some troops destroy a Sith party that includes Malgus.

Later in the "Deceived" cinematic trailer, however, Malgus, having appeared to survive the earlier attack albeit with a mask covering his nose and mouth, leads an army of Sith into the Jedi Temple on Coruscant, killing many Jedi.