Baron Praxis was an antagonist featured in Jak II. He was a tyrannical and corrupt autocratic ruler of Haven City who overthrew King Damas and ruled until his death, towards the end of Jak II. He served as the political adversary to the rebel Underground movement and in correlation as the personal enemy to Jak, being directly responsible for his painful acquisition of dark powers, spanning two full years as a subject to the Dark Warrior Program.
Styled as "His Eminence, the Grand Protector of Haven City", Praxis ruled Haven City with an iron fist, instituting an authoritarian military police known as the Krimzon Guard. He was the father of Ashelin Praxis, who has served as the governess of Haven City since his death.
Before Jak II
Little is known about Baron Praxis' past. He was some sort of high-ranking official during the rule of then-king Damas, and while it is unknown for how long he served, it was for most (if not all) of Ashelin Praxis' life, as she indicated that she lived in the Palace since she was a little girl. He eventually usurped the throne and betrayed his king, banishing him to the Wasteland and, with the help of Grand Council chairman Veger, further discontinued the House of Mar as the ruling dynasty in Haven City. At some point before or after coming to rule, Praxis led an assault on the Metal Head nest, resulting in the loss of most of the right side of his face, which was replaced with cybernetics. The anniversary of this futile event was mentioned in a propaganda station message during Jak II. Ashelin's mother, the Baron's partner, was never mentioned and her existence was never made apparent.
Baron Eco Fund
Praxis was an oppressive dictator and, among rescinding the freedoms of the citizens of Haven City, also enslaved lurkers and instituted a corrupt police force, known as the Krimzon Guard. When the Metal Heads attacked a part of the Shield Wall, compelling him to relinquish that sector of the city (then becoming known as "Dead Town"), he engaged in a deal with the Metal Head leader, facilitating a trade of regular shipments of eco to the Metal Heads for them to attack the city only enough to justify his unjust placement in rulership. This deal was underwritten by the Baron Eco Fund, with which the Baron generated various sources of eco revenue, including a mining operation at the strip mine and drill platform, as well as eliciting "donations" from citizens through propaganda.
Dark Warrior Program
Baron Praxis, as an early effort during the Metal Head Wars, initiated the Dark Warrior Program, which necessitated the apprehension of innocent civilians to conduct dark eco experiments on them, in an attempt to transform them into elite warriors.
Upon Jak's arrival into the future, Krimzon Guard commander Erol, accompanied by a squad of guards, were sent to arrest Jak in the Industrial Zone. After his arrest, Onin revealed that Jak had special powers, so the Baron focused his efforts on his new detainee. However, Jak was ultimately deemed a failure after mass amounts of dark eco injections which should have either turned him into an elite warrior or killed him, seemingly left him "nominal and unchanged." After Jak's escape, the Dark Warrior Program was presumably put to an end, as Baron Praxis gave the orders to "move forward with the final plan."
Upon Jak's jailbreak, he joined the Underground, a resistance movement aimed to depose Baron Praxis and re-establish the House of Mar as the ruling dynasty in Haven City. Throughout the game, the Baron has various confrontations with Jak, including two battles in the missions "Defeat Baron at palace" and "Defeat Baron in Mar's tomb" (during which he battled Jak with the squid mech and widow mech, respectively), as well as at the end of the "Win Class 1 race at stadium" mission.
Final plan and death
After the failure of the Dark Warrior Program, the Baron proceeded with the "final plan," which involved the acquisition of the last Precursor Stone which could hypothetically be cracked open using a piercer bomb, the energy of which would, by design, wipe out the Metal Head race "once and for all." What the Baron did not know was that if the Precursor Stone were to be violently cracked open, the energy released would destroy the entire planet and beyond. While Jak and Vin discovered this, the Baron contracted weapons merchant Krew to design a piercer bomb at the weapons factory (meanwhile building a back-up one for himself). However, Krew deceived the Baron and allowed the Metal Heads access into the city through ancient passageways in the Underport.
Shortly after the metal heads broke through, it is revealed that Kor is the Metal Head leader disguised as a human. Kor transformed himself into his natural form while meeting with the Baron at the construction site. Upon transformation, the Baron proceeded to charge him with his sword before being fatally wounded by a blast from the Metal Head leader. On his deathbed, the Baron reveals to Jak that he built a second, back-up piercer bomb where he hid the Precursor Stone. Jak then used the Precursor Stone to power Mar's gun, which would properly conduct the Stone's energy and effectively penetrate the Metal Head nest.
Praxis is a very tall, heavy-built, middle-aged human male. His proportions are thick, with heavy-duty clothing and armor. The upper right side of his face, along with his nose and entire cranium, have been mechanized, due to injuries he sustained while attempting to assault the Metal Head nest. He has reddish-brown hair, with streaks of gray accent and wears heavy, protective armor with a royal coat of arms, with various metallic plating and decorative aesthetics. He also wields a large sword, though he only uses it once in a suicide charge against Metal Kor. The sword itself appears to be a metallic blade with a flow of a green plasma-like substance, possibly green eco.
Throughout the game, Praxis appeared to be mentally unstable and austere. In the propaganda stations placed throughout Haven City, he often complained about how "lazy" the citizens are and how dirty the city is. Praxis was very power hungry and was determined to stay on the throne, even if it came down to making deals with the enemy. He was so obsessed with power, that he was even willing to sacrifice his own daughter to gain the Precursor Stone. Torn, Jak, and Daxter believed he would have followed up on this threat. He cared little about the feelings of others, treating Jak and lurkers like lab rats and slaves, respectively. In the end he partly admitted his defeat, calling Jak a supreme weapon and left the task of destroying Kor to him. It was also shown here that despite his many personality flaws he does have some honor, and does ultimately care for the safe-being of the city and its citizens, being willing to risk his life to fight the Metal Heads if need be. Praxis viewed himself as a saviour and genuinely sought to defeat the Metal Heads, but only so long as he remained ruler of Haven City.