The Star Wars: Rebirth timeline makes its most significant divergence in 18 ABY, built on the events of the last five years (available at http://swrebirth.wikia.com/wiki/Setting). The Jedi and Sith both had built a significantly larger presence than in canon, including a re-established Sith Order and Academy that mostly unknown to the galaxy. Frustrated with the inaction of the order and the stagnation they saw in the Empire, a faction within the Sith staged a coup in 18 ABY that targeted military installations and officers in a fast, bloody sweep. In the aftermath, many of the bases on Bastion had been destroyed and star destroyers crippled; in the wake of the destruction, Ta'ana declared herself the new Empress, with Daala serving under her.
The Republic responded by re-activating its military forces, and in a decision fraught with controversy, the Jedi Order became a part of the Republic military while the new Sith Empire began expanding through attacks on soft targets and sudden strikes on military facilities. Blockades against planets that rebelled against the Empire were common, and the Republic military often found itself stretched thin in its attempts to keep up.
In 19 ABY, the Sith Empire blockaded Bimmisari in a strike that none predicted and few understood, keeping the planet in an iron grasp for nearly a year as it based the majority of its fleets in sector. Frustration grew within the rank and file of the old Empire, with increased anger at the growing quagmire slowly killing the moral of the forces stationed on the planet. Republic strikes and rescue missions became more common and more successful until the breaking point in 20 ABY, where they sent the fleet to liberate the planet.
The retreat order came immediately, sending the Sith Empire's fleet to Yaga Minor; ranks began to break into Sith forces and Imperial loyalists as soon as the first ships arrived. The anger at the apparently pointless waste of lives and resources rapidly boiled over into a short, brutal civil war at the rallying point. Catalyzed by the arrival of a high ranking officer from the days of Palpatine's Empire, the loyalists attacked before the retreat was even finished, hunting down Ta'ana and the remaining Sith forces on Bastion shortly after. With the Sith leadership broken and the Imperial loyalists galvanized, the Moffs reclaimed their territory while the Sith retreated to Korriban to lick their wounds.
Now the Empire has begun a purge of Sith influence, while the dark side cult struggles to find its footing again in a galaxy that prefers to believe it destroyed. Some Sith have picked a path of open aggression, claiming they belong to a sovereign nation. Others have attempted to forge alliances with the Empire, while more have taken the opportunity to exert their power and influence in secret as agents of the Empire or members of the criminal underworld. The only certainty on Korriban is uncertainty.
With the immediate threat passed, the Jedi have begun to come back together as well, still divided over their sudden transition from monks and philosophers to military force; many Jedi who left in protest have yet to return, and the Masters are locked in a constant debate over the place of the Order in a galaxy that knows the Sith are out there somewhere. Other Force traditions have grown in the wake of the chaos, with Jedi no longer having the time to monitor them and the Sith lacking the resources to annex them. The Republic, meanwhile, keeps a wary watch over the Empire's territory, knowing another expansionist move could come at any time or any place.