At some point prior to 1899, Fussar became the ruler of the island Guarma. Using his new power, he built up connections in the city of Saint Denis.
Events of Red Dead Redemption 2
Saint Denis Chapter
Fussar is first seen in the Guarma chapter, when Dutch and Arthur sneak into Aguasdulces. It is here, that they see him along with a large group of his men taunting, and dragging Javier by a donkey following his capture.
Fussar eventually discovers the gang's true identity, and learns that they have a large bounty on their heads. He alerts the American Navy, and sets up gun batteries on the shore to stop them from leaving. The Van der Linde gang along with Hercule Fontaine assault these batteries, and then attack Aguasdulces to rescue the ship captain. Arthur bursts into the workers' cabin to rescue the captain, but is tackled by Levi Simon, Fussar's right-hand man. Simon holdes Arthur at gunpoint, and is about to shoot him, when Dutch enters the room and holds Levi at gunpoint, only to, in turn, be held at gunpoint by Fussar himself. A Mexican standoff ensues, which is resolved when Arthur kicks his rifle over to the captain, who shoots Levi in the chest. Fussar, however, manages to escape.
The gang then begins cutting their way to the ship, until they are attacked once again by Fussar, who is manning a gatling gun on a tower overlooking the port where their boat is docked. Knowing they won't be able to set sail while under the colonel's fire, Dutch and Hercule draw Fussar's fire as a distraction so Arthur can sneak towards a nearby cannon. Once he reaches it, Morgan shoots the cannon at Fussar's tower, blowing both up with one shot.