Grappa, a criminal Hutt, made his home on Genon. The Moldy Crow starship was once under his ownership, and he employed the services of Roark Garnet, a smuggler.
Following the demise of Galactic Emperor Palpatine in 11 ABY, Grappa formed an alliance with the Imperial Ruling Council and its leaders, Carnor Jax and Xandel Carivus. He aided Carivus by providing bounty hunters and conducted business with Boss Banjeer. Furthermore, he collaborated with Nom Anor. He orchestrated the kidnapping of Feena D'Asta and replaced her with a clone.
Throughout his interactions with both the Galactic Empire and Black Sun, Grappa's ultimate ambition was the conquest of the galaxy.
Within his Genon palace, Grappa engaged in racketeering, reaping profits from illicit ventures. Those underlings who disappointed him faced a gruesome fate: being thrown into a cage with a monstrous creature, their demise serving as entertainment. He had at his disposal several smugglers, bounty hunters, and pirates. One such group was Sol Mon's pirate crew, known for hijacking ships and pilfering their valuables for Grappa. This group included Tront, a Gamorrean guard with a strong dislike for droids, whose actions often led to Grappa having his protocol droid, 4/NG, repaired by his "techs."
Upon the arrival of an unidentified bounty hunter, Kenix Kil, at Grappa's docking bay, Grappa had him confined to a room prepped for his arrival. Grappa installed surveillance cameras to uncover Kil's true identity; however, Kil discovered and disabled one, further enraging Grappa.
During his time in power, Grappa held a meeting with Macus Kayniph. He provided Macus with gree spice in exchange for Feena D'Asta, whose clone was created to serve as a decoy in a sinister scheme. They toasted to the agreement. Unbeknownst to Grappa, Mirith Sinn, a new member of his court, overheard their entire plan.
Following his deal with Macus, Grappa dispatched [Tarrant Snil](/article/tarrant_snil], his new prisoner, with his associates, the Zanibar, and threw a party celebrating Kil's success. The celebration was cut short when Grappa received an unwelcome communication from "the faceless one."
Macus paid Grappa a visit, leading to another party. During this event, Mirith Sinn attempted to free Feena. As she made her escape, Grappa intercepted her and introduced her to Massimo, an old acquaintance. Aware that both women possessed knowledge of his hijackings, he sent them away with the Zanibar. When one of the Zanibar reported Kil's absence, Grappa, in a fit of anger, shot him with his own weapon. Macus intervened, prompting Grappa to fatally shoot him in the chest. This proved to be a grave error, as Y'ull Acib had explicitly forbidden any harm to Macus, threatening Grappa's life if anything were to happen to him. To explain Macus's death to Acib, Grappa orchestrated an "accidental" ship explosion, killing his entire court. However, this explanation failed to satisfy Acib.
When the Zanibar brought in Kir Kanos, Grappa recognized him as Kil. Learning that Acib wanted to see Macus alive, Grappa prepared to flee.
During a New Republic strike force raid on his palace, Grappa was surprised to see that Mirith Sinn had managed to escape the Zanibar. Sinn then imprisoned Grappa in one of his own cells, where he remained until Schmood, a court member who had not been on Grappa's doomed ship, released him. In return, Grappa shoved Schmood into the cell and locked it, seeking retribution for Schmood's earlier inaction.
As Grappa prepared to depart for Tatooine to meet up with Sol Mon, he was confronted by the Zanibar. When he refused to pay the agreed-upon price for capturing Kir Kanos, they chained him up, intending to use him in their next "ceremony."
Grappa exhibited extreme callousness, sadism, and ruthlessness. He displayed zero tolerance for incompetence or disloyalty, frequently executing those who failed him, often by handing them over to the Zanibar for their rituals. He was easily provoked and prone to irrational behavior when faced with any form of challenge or disagreement, as evidenced by his murder of Macus Kayniph, disregarding the consequences of severing his ties with Black Sun.