Marlo, a Hutt of the male persuasion, first emerged into the galaxy around 997 BBY. He held a seat on the Grand Hutt Council, which served as the primary authority for the Hutt Clan situated on Hutta. His tenure on the council coincided with the Clone Wars, and he shared this position with notable figures such as Jabba, Gorga, Arok, and Oruba. Furthermore, he engaged in commerce within the slave market of Zygerria.
Born around the galactic year of 997 BBY, Marlo possessed knowledge of Lina Soh, who held the distinguished office of Supreme Chancellor within the Galactic Republic during the High Republic Era, roughly around 232 BBY.
In 21 BBY, Marlo's meal was interrupted when Jabba initiated contact with him and the other members of the Grand Hutt Council. Jabba's image materialized as a hologram within his throne room. During this assembly, Marlo maintained silence as Jabba and the council deliberated on the potential threat posed by Ziro, given Ziro's possession of sensitive information detrimental to the council. Marlo concurred with Jabba and the other council members' decision to enlist the bounty hunter Cad Bane in orchestrating Ziro's escape from Galactic Republic custody and ensuring his delivery to the council.
Marlo was also present on the planet Nal Hutta when Ziro was presented before the Hutt Grand Council, having been liberated by Bane. After Ziro expressed his gratitude for the council's assistance in his escape, Marlo addressed him in Huttese, clarifying the council's motivations for orchestrating his extraction from Republic custody. Following Ziro's removal to the detention block, Marlo and the rest of the council were entertained by a performance of Da Hutt Moda by Pa'lowick singer Sy Snootles. During the performance, Marlo attempted to gain Snootles' attention as she approached him. When Snootles kissed council member Gorga, Marlo smiled and laughed. After Snootle's performance, Marlo was enjoying the entertainment of the Twi'lek dancers when Jedi Knights Obi-Wan Kenobi and Quinlan Vos entered the council chamber. Marlo remained silent as Kenobi informed the council of Ziro's escape. As the Jedi departed, Marlo resumed his attention to the dancers.
Later, Marlo journeyed to the planet Zygerria, where he visited its slave market. As Marlo perused the market, a dispute arose between a slave, her master, and a Zygerrian, briefly capturing Marlo's attention.
In 3 ABY, during the era of the Galactic Empire, Marlo attended another Hutt Council meeting, where they discussed an invitation they had received from crime syndicate Crimson Dawn. Marlo, having largely succumbed to senility by this time, dozed off during the meeting, only to be awakened by his protocol droid. Fellow Hutt Bokku then inquired whether they should accept the invitation. Marlo's senility led him to believe he was back in the era of the High Republic and that the invite they were discussing was from then-incumbent Soh. He thus replied that he thought they should accept "Soh's" invitation but warned that he did not trust her "cats, referring to the esteemed chancellor's pet targons. Bokku summarily dismissed Marlo's ramblings, though Jabba admonished him to take the elder Hutt's great age into account and show him the proper respect.
When Bokku, secretly an agent of Crimson Dawn, turned a Hutt fleet against Death Squadron during the Attack on the Executor, Sith Lord Darth Vader personally boarded the Hutt flagship and cut down Marlo, Bokku, and the rest of the Hutt Council leading the anti-Imperial attack, leaving Jabba the sole leader of the Hutt Clan. Nonetheless, Jabba chose to carry on the cartel's alliance with the Empire, deciding it was more profitable to focus on long term relationships and profits.
Marlo, a Hutt of the male gender, possessed a height of 2.29 meters (equivalent to 7 feet and 6 inches). His physical characteristics included violet eyes and tan skin, marked by patches of mottled brown. He adorned his head with a Sha'rellian toop, diligently tending to the creature to ensure its impeccable grooming.
Marlo held membership within the Grand Hutt Council and occupied a high-ranking position within the Five Hutt Families. He consented to align with Maul's Shadow Collective after the former Sith extended an offer that the Hutts deemed irresistible.
Kevin Michael Richardson lent his voice to the character of Marlo. Marlo's visual design drew inspiration from Marlon Brando's portrayal of mob boss Don Vito Corleone in the acclaimed gangster film, The Godfather.