"You Don't understand what power I want from you, yet, you will all suffer..." - Gol speaking to all Jedi and Sith, who ambushed him during his arrival to Mustafar.Gol comes from a variety of universes, which all have a different outcome or has more explanation.
STAR WARS CANNON
Gol was never present or heard of at this time, he may have been in the canon but never to be seen.
STAR WARS LEGENDS
Gol in this universe shares the same as his counterpart in the Cannon Universe.
UNIVERSE A: THE BELONGING
Gol achieved his goal in this universe, nothing but him was left and his new army. All Jedi and Sith were left in extinction. Gol replaced the Galaxies Armies with his own, he called it the "The Divided Hive", which represented his full army he created from other Galaxies he has taken over the course of his life, which all come together as one.
UNIVERSE B: THE FALLEN
Gol was overthrown by both Jedi and Sith, the Jedi and Sith were forced to team up against him, they saw him as a weakling standing alone, he was captured by an unnamed Sith.
Most of his time
Gol was a unique being in his own ways, he was different from the average human, The lifespan on his Galaxy was for more than 50,000 years, Gol wanted to escape from his home planet and his galaxy, wanting the be left alone. He created his own army known as "The Hive". Gol was manipulated with the force, it is clear he has known this for a very long time in his life, as he uses it commonly in his lightsaber fights. Gol even said he has taken over more than 10 Galaxies not far from the current one he is present in. Even though they happen to be so many light-years away. The technology on Gol's Galaxy was far more advanced, though since he came with only a small army and his equipment, he scavenged from the Galaxies' planets and even killed the people who were present.
During his time
During his arrival, both Jedi and Sith knew there was a greater threat above them. They all felt a disturbance they've never felt before in history. Gol's presence was assured, but no one knew who it came from. Many many disappearances of Jedi and Sith became more common, with no one aware who was behind it. When Gol would kill an enemy who was force sensitive, he would take what little force power they had left, he was a Light and Dark side user, giving him more of the advantage in combat. After Gol's force made the other force sensitives feel trouble, Jedi and Sith actually started communicating through the ways of the force to find answers of the disappearances later on.