Gallius Rax, originally known as Galli, is a major antagonist in the Star Wars franchise. He is the main antagonist of the 2015-2017 novel trilogy Star Wars: Aftermath and the overarching antagonist of the 2017 video game Battlefront II.
Galli was originally an orphan who lived on Jakku until he met Emperor Palpatine. Envisioning a great destiny for Galli, Palpatine took him as his protégé and later made him a member of the Galactic Empire, adopting the name Gallius Rax. Following Palpatine's death during the Battle of Endor, as part of Palpatine's Contingency, Rax becomes the de facto ruler of the Empire while coordinating its destruction for outliving Palpatine, but Rax secretly plans to create a new Empire despite that this wasn't part of his former master's plans, planting the seeds of what finally turns into the First Order.
While there is no official image of Rax, many fanart has spread out revealing what he may look like taking into account the physical traits the novels give about him, including his hair, eye and skin color as well as his Imperial uniform.