Sakazuki is perhaps the most strident follower of Absolute Justice in the entire series, to the point where his extremism prompted his fellow admiral Aokiji to oppose his promotion to fleet admiral and resign from the Marines after this effort failed. Because of his actions, Sakazuki is one of the main antagonists of the Marineford Arc and, after his promotion, he became one of the central antagonists of the series. Sakazuki is an incredibly tall, light-skinned, unusually muscular man (the most muscular of the former admirals and being on par with Sengoku and Garp). He's about as tall as his fellow admirals, with a square-shaped face, very pronounced facial features, and short black hair. He stands at 306 cm (10'), making him taller than other massive characters like Jinbe, who is 301 cm. He usually wears a standard Marine cap and sports a crimson, double-breasted suit, decorated with what appears to be a pink rose on his left buttonhole. Unlike many high-ranking Marines, he does not wear a tie, but instead leaves his light red colored flower-patterned shirt unbuttoned, showing his muscular neck and part of his tattoo. He wears black gloves and black shoes. The tattoo on the left side of his chest is black (light-blue in the anime), containing numerous images of flowers integrated into its design. Sakazuki's tattoo has flame-shaped edges, and it extends from the admiral's left shoulder to his hip, covering part of his back and ribs. He has another, smaller tattoo in the shape of a black sword on his right deltoids and a small part of the biceps.
39;s neck and face are scarred, and a chunk of his right ear is missing.
In the anime, his eye color is seen to be brown, and this was also shown in a colored drawing by Eiichiro Oda. In his youth, Sakazuki wore an open red shirt, as well as a set of khaki pants held up with a loosely tied yellow-orange ribbed belt with a silver bullseye shaped buckle, and a pair of red sneakers. He also carried a katana on his back. Twenty-two years ago at the Ohara Incident, he wore a simple white Marine cap under a dark gray hood that seemed to be a part of a cloak he wore beneath his suit, or Marine coat. Until getting off his chair in order to destroy an incoming iceberg during the Summit War of Marineford, his face was always hidden by the bill of his cap. As a child, Sakazuki still had the grim disposition he retained as an adult. He also wore tattered clothes and carried a dagger. He wore a cap similar to the Marines' cap he would don in the future, except it has the kanji for "justice" instead. After the timeskip, as a result of his intense battle with Kuzan at Punk Hazard, the right side of Sakazuki's neck and face are scarred, and a chunk of his right ear is missing. In addition to his injuries, he also grew a mustache and goatee. He has also replaced his trademark red suit for a white one, similar to what Sengoku wore when he was Fleet Admiral; however, Sakazuki still wears the same floral pattern shirt underneath and doesn't wear his black signature gloves.
He continues to wear the standard Marine cap, though unlike his predecessor's, it does not have the life-sized seagull on top. He is also frequently seen smoking a cigarette. Later during the Wano Country Arc, he appears to be wearing a darker suit once more, possibly a red one like his pre-timeskip suit. While he is a strong and capable leader who has done well to consolidate the power and prestige of the Marines, Sakazuki would be best categorized as an extremist and highly dogmatic. He is an adamant believer in Absolute Justice and is ruthless in his maintenance of it, his derived motto of being "Thorough Justice" (徹底的な正義, Tetteiteki na Seigi?). He has a stern, dead-serious disposition, is grim, expressionless, and was the most ruthless out of three admirals pre-timeskip. This has given him a very fearsome reputation, but of greater concern is his dogmatism, which may end up making the Marines into a force that is worse than the enemies they hope to eliminate. Despite this disposition, Sakazuki seems to be able to restrain himself at times, having chosen to spare the life of Jewelry Bonney and her crew after they were left beaten and tied by the Blackbeard Pirates for the then-admiral to salvage, and letting his colleague Aokiji left the Marines after he lost a ten-day duel for the position of fleet admiral.
His extremism has given him a borderline, if not outright fanatic demeanor.
During the Buster Call attack on Ohara, Sakazuki's beliefs led him to go as far as destroying a refugee ship full of innocent people and Marines simply because of the slight possibility that a scholar could be hiding on board, an action that disgusted Vice-Admiral Kuzan (who called him a "fool" and an "idiot" for overdoing things). Sakazuki's logic was that if even one of the scholars of Ohara had escaped with it, the entire mission would have been a failure. His extremism has given him a borderline, if not outright fanatic demeanor. He is incredibly rigid and absolute in his beliefs, showing little compassion for anyone or anything, and is ruthlessly willing to do whatever it takes to serve his own goals, no matter the cost. He mostly sees the Marines as an extension of himself and his own beliefs, willing to kill those who disagree with him, and showing little if any care for people placed under his charge. While this has made him extremely powerful and feared among pirates, the same fear inspires discontent and loathing by his own men, causing him to lose a very useful and powerful ally in Kuzan because of it. Garp was also enraged that his fanatic obsession for destroying pirates, in the death of Ace and the near death of Luffy, though it is unclear if a rift between them has further deepened or caused further dissent among Marines who believe in either's viewpoint.
As Fleet Admiral, Sakazuki holds immense pride in the name of the Marines.
The best example of his absolutism is when he attempted to kill Koby for his plea to stop the war, only to be stopped by the timely arrival of Shanks. His extremism also caused him to bar Admiral Fujitora from ever entering a Marine base due to his prostration in Dressrosa, though it was mostly because Sakazuki couldn't stand to see his version of justice and honor shamed because his enemies showcased its own failure. Fujitora rightly pointed out that Sakazuki's version of Justice had no credibility or honor in the first place if it was that fragile, which only inflamed Sakazuki's rage further, seeing it as a personal slight. Additionally, he has no tolerance for Marines who desert their posts, to which the only consolation he does offer is that they should not dishonor their families by running away. Caesar Clown also believed that Sakazuki would desire his ideas of mass-murder weapons and inhumane experimentation on prisoners, in contrast to the more pragmatic Sengoku. To Akainu, any Marine who is not willing to fight for justice is not worthy of being called a Marine. Despite all of this, even Sakazuki could not come to kill his former compatriot, Kuzan. As Fleet Admiral, Sakazuki holds immense pride in the name of the Marines. For example, when he learned that Fujitora had let the world know of what transpired in Dressrosa, Sakazuki was furious.
His pride is so great he would rather cover up the ordeal to ensure that the Marines are adamant and credible to his doctrine of Absolute Justice. This conceited behavior even led to him yelling at the Five Elders for declaring Doflamingo's resignation from the Warlords of the Sea as a false report, as he knew the world's confusion would damage their trust in the Marines as well as the Marines' reputation. This shows that he does know the value of public trust, but thinks more in terms of the shame losing it brings to the Marines, rather than the morale and good standing of his men. Despite his position as an admiral prior to promotion, Akainu is willing to lie to and deceive his enemies in order to achieve Justice. Whitebeard to get Ace angry enough to stop his attempt at escape. He finds people who attempt to interfere with him as nothing more than irritating obstacles. Furthermore, he seems to be unafraid of older legends, as when Whitebeard told his men not to be intimidated by Garp due to the Marine being an old man, Akainu mocked Whitebeard's comment, saying that Whitebeard was also from the same generation as Garp before attacking the Emperors. While other Marines such as Sengoku and Garp share a decent amount of respect for their accomplished enemies, Akainu has no such empathy, instead disparaging them at every chance he gets. Prior to Sengoku making it public, Akainu was one of the few who knew that Luffy was Dragon's son.
39; activities and vice versa.
It is unknown if he has some past relationship with Dragon, or if it was simply common knowledge among the higher ranking Marines that Dragon is Garp's son. As such, Akainu deems that Luffy's mere existence, due to being Dragon's son, is enough to be a threat to the world and therefore must be eliminated. In fact, Akainu's beliefs about heritage run deep enough that he declares that even if every other pirate escapes, he would personally ensure that neither Ace nor Luffy were allowed to leave the war alive due to their bloodlines. This conviction fueled Akainu to the point of actively hunting Luffy himself, even though Blackbeard was destroying Marineford at the time. Sakazuki does not see it as the business of the World Nobles to interfere with the Marines' activities and vice versa. This was proven during his confrontation with the Five Elders, where he disparages them for permitting the Celestial Dragons' CP0 to falsify Donquixote Doflamingo's resignation from the Warlords of the Sea, even questioning whether the Five Elders are the Celestial Dragons' puppets. Surprisingly, Sakazuki can demonstrate a sense of caution in regards to battling pirates or causing disturbances in global affairs. This was seen when he didn't attempt to attack Shanks when he arrived at Marineford to save Koby.
39;s life for voicing his objections for taking the war too far.
Also, despite Borsalino's request to travel to Wano Country to deal with the possible alliance of the Beasts Pirates and Big Mom Pirates, he declines it citing that Wano's military strength is an unknown factor and they are not within their jurisdiction. As the Marine fleet admiral, Sakazuki has command over the entire organization. Marines respect him and use to call him "Admiral Sakazuki" most of the time, as opposed to his epithet. Nevertheless, his ruthless adherence to "Absolute Justice" has made his colleagues fear and despise him, especially Aokiji, who called him a fool for taking things too far. In turn, Akainu will easily kill any Marines who contradicts his beliefs, as he executed a soldier for leaving his post in fear, and even made an attempt on Koby's life for voicing his objections for taking the war too far. Upon Sakazuki's rise to Fleet Admiral, Kizaru became a confidant to share his counsel, often offering helpful advice and being someone for him to share his personal frustrations over the growing threat of piracy, especially the Straw Hats. Kizaru has shown to be the closest thing Sakazuki has to a friend among the Marines. While it is unknown what their relationship was like before, Aokiji has had nothing but hatred for Akainu ever since his horrendous action during the Ohara Incident, calling him a fool for overdoing things.
When it was announced that Akainu would succeed Sengoku as fleet admiral, Aokiji strongly opposed this and dueled him for the position. Their fierce battle ended after ten days with Sakazuki achieving victory. Refusing to serve under his former comrade, Kuzan decided to leave the Marines and resign from the position of admiral. Though Sakazuki mocked Kuzan's decision when it was brought up by the Five Elders, he also claimed to show no concern for his activities. Additionally, though their battle was supposed to be to the death, Sakazuki - in a rare act of kindness - chose to spare Kuzan upon his victory over him, rather than put him to his end. Akainu also did not show any respect to Monkey D. Garp, despite the old vice admiral being a "hero" who was eligible for the position of admiral, due to him being from the previous generation, but mostly for sharing his lineage with criminals like Dragons and Luffy. Garp, in turn, tried to murder Akainu for executing Ace, and had to be restrained by Sengoku. It is unclear whether this has caused a further rift to develop between the two men or caused any problems within the Marines that prefer Garp or Akainu's version of Justice. Akainu did not seem to have any problems with Sengoku when he was his subordinate before the timeskip. This was seen when he grudgingly complied with Sengoku's order to end all hostilities of the Marineford War and permitting the Whitebeard Pirates to leave.