Jerec was a former Jedi Master and a former Imperial Inquisitor. He was a member of the, Force-sensitive, Miraluka species.
In his early years, a young Jerec was brought to the Jedi Temple to be trained after being discovered as a Force-sensitive. However, not all members of his species were a part of the Jedi Order. He eventually became a Jedi Master and a skilled archaeologist.
In 22 BBY, Jerec became a Jedi General during the Clone Wars, commanding a battalion of clone troopers.
He survived Order 66 and turned to the Dark side of The Force, becoming an Inquisitor for the, newly formed, Galactic Empire.
He led an attack on the Rebel-aligned planet of Sulon, personally killing twenty-five soldiers. He then interrogated and killed Morgan Katarn on his flagship, the Vengeance.
After the Empire's massive defeat at Endor, Jerec began his search for the Valley of the Jedi, to give him enough power to become the new emperor of a Reborn Empire. After a fierce duel, he was killed by Morgan Katarn's son, Kyle Katarn, ending his reign before it even began.
He commands a Vengeance-class Super Star Destroyer, which is one of the most powerful space units in The Pentastar Alignment's arsenal. However, much like the Executor SSD, it has a blind spot in the rear of the ship, making it vulnerable to enemy attacks in the back.
It gives the Pentastar Alignment two different types of SSDs at the start of the game, making it the most powerful faction, hero wise, at the cost of being very weak, economic wise.
There is a known bug where, if you auto-resolve a space battle while Jerec's in your fleet, you will lose him because the game has designated him as a ground hero (Despite his space battle capabilities).
Jerec fights as himself on the ground and has Force Lightning and Saber Throw as his special abilities. It's best just to keep him in orbit of a planet due to the firepower his SSD has.
Note: As of 2.2, Jerec and the Vengeance are split off from one another (To, both, get around this known auto-resolve bug and make the faction a bit more balanced).