Phylus Mon was born and raised on Vinsoth. During his childhood, he felt a natural connection with the wild animals in the forests. Phylus Mon was able to train them easily, because he was Force-sensitive. Eventually, Phylus Mon learned to find a great pleasure in big-game hunting and in the further mind-altering of the prey.
Phylus Mon's family business was slavery, which was also a traditional occupation for a Chevin. Chevins usually dealt in Chev slaves but Phylus Mon, while still not rejecting Chevs, preferred other more exotic species, mostly huge beasts whose primitive minds he could reshape before selling them.
During the following years, Phylus Mon continued dealing in slaves, but his business began to diverge from his family's. Guided by the dark side of the Force, Phylus forgot the happiness of his childhood's animal training and became a hating, vicious sentient: he only looked for exotic, hideous fauna as gladiatorial beasts, and he searched for the ultimate beast who could defeat any other creature. Using the dark side and a three-tailed glowing barbed whip, he captured and fought animals and sentients alike, both as prey or because they stood in his way to the prey, from Geonosis to Coruscant's Underworld. He was known to have defeated Wookiees, gundarks, and dragonsnakes. During all this fights, his skin adapted and became so hard that most personal weapons were unable to pierce it.
Whenever a new slave joined Phylus Mon's assets, Phylus Mon ordered his surgeons to perform an operation on the slave. An explosive was implanted near the slave's heart or any vital organ, depending on the species. Phylus Mon himself had an emitter near his own heart so that, in case of his death, a signal would be sent to all the explosives in his slaves, killing them instantly. The explosives could be deactivated by ionizing them (although, to avoid this, Phylus Mon forbid his slaves from using ion weapons). However, Phylus Mon's emitter was protected in a metal shell and could not be deactivated using that means.
Phylus Mon kept both a "zoo" of slaves for their sale and/or training (commonly trained by Phylus Mon himself), and an "entourage" of trained personal slaves, with the latter sporting the emblem of his company, a pair of crossed Rancor claws, and the former sporting both that plus a bright red circle in the left side of their chest. Phylus Mon said that his minions were not slaves, but free people, and his minions perpetuated this fiction. In fact, Phylus Mon paid them a salary. However, they could not leave Phylus Mon's employment or they would be tracked and killed. Nevertheless, those slaves were so broken that most of them would not even think of leaving Phylus Mon.
Phylus Mon liked to use the Force as a weapon. He avoided a fight until he had time to use his own powers to improve his physical abilities and the damage of his whip (which glowed when ready). The extent of his powers was unclear. Rumors suggested that, when trying to capture battlebirds from Orimanther, he meditated until he learned to use the Force to create a storm, only to stop them from flying.
To avoid combat and to discourage would-be assassins, Phylus Mon always kept the entourage of slaves with him. He combined fast attackers, powerful defendants, Force-users, and creatures form his zoo. Throughout the years, Phylus Mon found a number of Force-sensitive Chevs and enslaved them. Nevertheless, should that fail, he always had some escape routes and secret defenses.
A rumor suggested that Phylus Mon had a trained wampa even more dangerous than himself. It was true: Phylus Mon found Ku-Kak the Force-sensitive wampa in a remote ice planet, probably Hoth. Phylus Mon discovered the rare ability of Ku-Kak. He took the animal and trained him, although only in Chevin so that Ku-Kak would be unable to obey orders from other people. He also trained Ku-Kak to hate Jedi, and to recognize them because of their lightsaber. Strangely, however, Phylus Mon avoided the Jedi Order and never killed a Jedi or a known associate of a Jedi.
Another of Phylus Mon's known associates was Anzat Force-sensitive Mischa Vorfren. Ku-Kak provided Vorfren with the lightsaber of Jedi Knight Ish-Bel Tur, and of course the Wampa learned to consider Vorfren an ally (else he would attack Vorfren when seeing his lightsaber). Phylus Mon named Ku-Kak his personal bodyguard and armed him with a Sith sword he had found some time before.
Another important member of Phylus Mon's organization was Yerj, a Force-sensitive Barabel who was owned and trained in a probably dark-side facility before Phylus Mon bought his contract circa 32 BBY. During one decade, Yerj tracked animals and people for Phylus Mon, including at least one female Jedi. Yerj's successes earned him a reputation in Phylus Mon's files.
Phylus Mon also bought the "freedom" of Nalz, a Spiner in a freak show. Nalz believed that Phylus Mon had bought his freedom, and as such, Phylus Mon did not own Nalz (however, Nalz was trained and an explosive was inserted in his chest). Nalz worked for Phylus Mon as a part of an elite strike force, knowing that Phylus Mon was a criminal. However, Nalz was known to respect Phylus Mon's criteria.
Phylus Mon found a freed albino Trandoshan, Gorak, and he offered her a job dealing with his animals; she showed a special skill when dealing with acklays and rancors. She also learned to respect Phylus Mon's ways (a respect that was not widely spread in Phylus Mon's security entourage).
Phylus Mon also bought the "freedom" of Wookiee fighter Kaarror. Phylus Mon had found Kaarror fighting in an arena, liked him, and earned some money betting on him. Instead of keeping Kaarror in his organization, he allowed him to join (or sold him to) the Kalmec criminal organization.
Phylus Mon was believed to be the man behind Cularin-based smuggler Rufus Trammel. Although Trammel, as a "dealer in exotic items", was tolerated in Cularin, Phylus Mon, was infamous there. Cularin crime lord Nirama would have tracked and killed Phylus Mon should the Chevin reached his system, and some fringers would simply leave Cularin in that case.
At some point, Phylus Mon obtained an enormous starship, the Animiasma. This ship could run blockades and avoid detection, using some unclear method. It had different defense lines against attacks, including drone starfighters. Phylus Mon's personal quarters were under the zoo, but he always kept an emergency exit to his personal shuttle.
During the beginning of the Clone Wars, Phylus Mon was contacted by Len Markus. Markus had been a criminal on Cularin and he had left the system with a Sith artifact known as the Darkstaff. During his escape, all of the Cularin system disappeared from the galaxy due to the Sith magic of the Staff, and Markus was believed to have died.
Markus had discovered that the Darkstaff could be used to create Sith battlelords. A Sith battlelord was the absolute master of his troops: any soldier attempting to leave his Battlelord would cause extreme pain (and eventually death) to all the regiment, including himself. Phylus Mon was specialized in exotic slaves, and a "slave army" was exotic enough to get his attention.
Markus offered Phylus Mon the process to create a Battlelord, if Phylus Mon could repair the Darkstaff. Markus provided Phylus Mon with a Sith tome, but it was in Sithese. Phylus Mon found a slave who could read Sithese, obtained a translation of the tome, and killed the slave.
Phylus Mon made a deal with Dark Jedi Karae Nalvas, who would like to become a Battlelord. However, Phylus Mon planned to betray Nalvas and use him to learn how difficult to kill a Battlelord can be. Phylus Mon also called his former slaves Kaarror, Gorak, Nalz, and Yerj, who would become his first Battlelords; however, Phylus Mon did not inform them of his scheme.
During this preparation, Phylus Mon discovered that a powerful darksider somewhere in the Core Worlds had a special interest in the Cularin system and the Almas Academy.
Phylus Mon intended to repair the Darkstaff by feeding it with the Force essence of living beings, which could be handled using the Battlelord-creation ritual. Phylus Mon then traveled to Cularin in the Animiasma, outwitted the Thaereian blockade, and went to the planet Almas. Mon wanted to enter in the Almas Sith fortress and perform the rituals there.
While orbiting Almas, Mon kidnapped some Force-sensitive native Tarasin children, including Li'Iri, Honna, Tiscak, and Kaj. Phylus Mon personally whipped all of them, marking the face of Tiscak, and held them in his zoo.
The Sith fortress had been taken by the Jedi of Almas Academy, but it was not completely explored. However, Mon had information on the fortress layout that the Jedi lacked. Phylus Mon intended to raid the fortress, killing some of the Jedi guards, and perform the rituals in Darth Rivan's crypt.
Mon attacked during a sandstorm along with his five future Battlelords, Ku-Kak, three gundarks, and three other minions. They dealt easily with the six Jedi guards in the south entrance. Two of those Jedi, Valiri and Constanten, were knocked down but kept alive, as they could be used in their first tries. A third Jedi, Vorlocca, who had died in the attack, was dragged to the insides of the fortress, and left there with the gundarks eating the corpse as an ambush for the Jedi search teams. The other three Jedi corpses remained in the doorway. Other Jedi in the fortress did not interfere, but tried to contact the Academy.
Mon probably used Force-induced illusions and the sandstorm to avoid being detected (although Ku-Kak's footprints remained as a proof). Phylus Mon then avoided security cameras and even heat signatures, and then reached Darth Rivan's intended crypt (Rivan himself had not been buried there) and ritual chamber.
Mon and his minions placed the Darkstaff in Rivan's altar and performed the ritual, while in the process humiliating the ghost of Rivan's disciple Darsin. Although the ritual was performed correctly, it did not link the Battlelords with any soldier. Instead, the ritual uprooted the Force essences of the victims, trapping them in a crystal pyramid so that the Darkstaff could feed on them. The victims' bodies were still alive, but unable to move or think. The Darkstaff nevertheless appeared to be repaired, or at least more repaired than before.
Phylus Mon and his minions left the seven empty bodies and abandoned the fortress some three hours after they had entered. Four hours after the attack, Phylus Mon's ship left the orbit and disappeared. Phylus Mon then steered the Animiasma to Cularin asteroid belt, where he could study the Darkstaff and try to discover what had happened.
Jedi Master Lanius Qel-Bertuk of Almas Academy sent different search groups to the Sith fortress, looking for the missing Jedi. They found all of the empty bodies and Qel-Bertuk discovered Phylus Mon's implication. He also correctly thought that Phylus Mon was probably the mastermind after the Tarasin children kidnapping.
Meanwhile, the Darkstaff grew stronger in the Animiasma. It tried to impregnate her with its essence, trying to make the ship a part of itself. It was transforming the ship in a dark side nexus. It also used the ship's sound system to distribute a sound causing confusion and horror to the crew (although Phylus Mon's chambers apparently were unaffected).
However, Almas librarian Oden Malksch accidentally entered the empty body of Karae Nalvas. Malksch felt the body's connection with its Force essence and its need to join it. The body felt the essence and, following that track, Malksch could find Phylus Mon's lair. Master Qel-Bertuk organized a team that would go to recover the stolen essences of the two Jedi and the others.
Phylus Mon was focused on the Darkstaff, so he was unaware of the intrusion. He was trying to analyze the Darkstaff in his room, with his usual security entourage around him (in this case, Mischa Vorfren; Blood Carver gunner Ke Len; Chev Force-sensitive slaves Drik, Niv, and Tosh laying at his foot; eight Coruscani Ogres and twelve Mantessan panthacs; plus Ku-Kak hidden). Suddenly the Darkstaff mysteriously disappeared from his sight and, seconds after that, Qel-Bertuk's team entered his room.
Phylus Mon threatened the team with a code phrase that alerted his entourage: the Chevs began using their Force skills to boost the rest of the entourage, Vorfren showed, but did not light his lightsaber, and the others began taking aim.
Phylus Mon intended to use his powers defensively during this fight and to maintain his position, as he could reach an emergency exit only by pushing a button in his throne. He thought that he could not be killed, as he could threaten his enemies with the death of all the slaves. Even more, he thought he could avoid capture by threatening with suicide.
At some point during these events, Nirama learned that Phylus Mon was in Cularin, and offered a reward on his head, live or dead.
Two of the three questions in the Critical Events Summary of A Mon Alone are related to Phylus Mon: one about his own destiny (dead, captured or escaped), and the other about all his slaves' destiny.