Marechiyo Ōmaeda is a large man (almost twice the height of his captain, and just over four times her weight). He claims that he is plump, which is a sign of his good living and wealth. He has black hair, and wears the standard Shinigami robes with a large purple collar. He is often seen wearing expensive, personalized jewelery.
Ōmaeda is an arrogant and dull man. He is cowardly, loud, vain, elitist, snobbish, greedy, and sluggish. However, contrary to his normal behaviors and mannerisms he is exceedingly loyal to his captain, to the point that he is willing to fight along with his captain against enemies a lot stronger than himself. His willingness to take an attack aimed at his captain, act as a temporary decoy, and cut off Suì-Fēng's arm at her request shows that Marechiyo holds a great deal of loyalty to his captain. Despite his arrogance, Ōmaeda has shown himself to be deceptively sharp in combat enough to catch his opponents off-guard.
Ōmaeda likes to eat fried rice crackers (abura senbei) wherever he is, and his captain is known to beat him up when the crumbs from the crackers fall on her hair. However, he does not like fish.
Marechiyo is shown to come from a rich family. As is typical of many rich families, he has a long name,Marechiyo Yoshiayamenosuke Nikkōtarōemon Ōmaeda (大前田 日光田郎右衛門 美菖蒲介 希千代,Ōmaeda Nikkōtarōemon Yoshiayamenosuke Marechiyo). His father is named Marenoshin, his mother is Mareka, his older sister is Maremi, his younger brother is Marejirōsaburō, and his younger sister is Mareyo. With the exception of Marechiyo's younger sister, all the other family members closely resemble him. Mareyo is more normal looking and sweet, which shocks Izuru Kira, Renji Abarai, and Shūhei Hisagi. Marechiyo thinks his younger sister is ugly. It is also remarked here that he enjoys inviting commoners to his home, probably only to show off his wealth. He is often taken advantage of by his fellow Lieutenant Shūhei Hisagi, who often comes and eats Marechiyo's extra food when he is low on cash.
Marechiyo's specialty is making bracelets, as he can craft gold. All the jewels seen on him are made by himself. He owns a factory named "Ōmaeda Gem-Precious Metals Factory", which makes jewelery. He fries any slacking workers with his yet unknown ability, the "Marechiyo Chop".
Being rich, he was able to install the 2nd Division quarters with floor heating, automatic doors and cooling/heating system.
Ōmaeda is first seen walking through the 2nd Division Headquarters with his captain while eating rice crackers, complaining about how annoying it is that drifters have entered Soul Society, someone has died and now everyone is questioning whether or not Rukia Kuchiki's planned execution is legitimate. Figuring that the superiors already made their decision, he considers the issue pointless conversation. Suì-Fēng tells him that she has no interest in whether it is right or wrong, as she only cares about executing her orders as captain of the Gotei 13. All who get in her way are her enemies and all enemies must be slain. Ōmaeda denotes that he understands, before Suì-Fēng promptly tells him that the same goes for him as well. She explains that he should know where his loyalties lie and should he get in her way he will become her enemy. Ōmaeda smirks and states that he will remember that.
Ōmaeda is later seen standing next to Suì-Fēng awaiting for the execution to commence. Suì-Fēng comments to him that the attendance is poor, as only the 2nd, 4th and 8th Divisions have arrived, while the absences of the 5th, 11th, and 12th are expected. Ōmaeda stands amazed when the Sōkyokubegins to release. Shortly after the arrival of Ichigo Kurosaki, Ōmaeda bears witness to the destruction of the Sōkyoku by the intervention of Jūshirō Ukitake and Shunsui Kyōraku, Suì-Fēng yells to Ōmaeda to stop them but he is too surprised and caught off guard by the entire situation.
After Ichigo successfully saves Rukia and hands her to Renji Abarai who runs off with her, Suì-Fēng orders him to go after them, soon followed along by Chōjirō Sasakibe and Isane Kotetsu. He releases his Zanpakutō to fight Ichigo, but is beaten in mere seconds after the release of his Shikai was shattered by a bare-handed Ichigo, and he is knocked out with the same punch. He and the other defeated lieutenants are retrieved by Retsu Unohana, where he and Sasakibe were healed by Minazuki, Isane and by her captain directly.
When Aizen, along with his top three Espada and their Fracción arrive to attack the fake Karakura Town, he along with his captain are amongst theGotei 13 members sent to defend it. He comments to Suì-Fēng how Sōsuke Aizen, Gin Ichimaru, and Kaname Tōsen reiatsu is incredible as is usual, Suì-Fēng tells him that he can leave if he wants. Ōmaeda and all the other Shinigami in attendance gaze in awe as the Captain-Commander releases his Shikai.
He panics when Baraggan Louisenbairn sees through the fake Karakura ruse before he finds out that Ikkaku Madarame, Yumichika Ayasegawa, Izuru Kira, and Shūhei Hisagi are guarding the pillars keeping the real Karakura Town in Soul Society. He then complains about how he thought they had been excluded from the mission. He asks if the others knew about this, in which they did and Suì-Fēng said she told him, but thinks that she may not have told him.
After the fight for the pillars are successfully defended, the fight between the captains and the remaining Fracción and Espada begin. He engages in battle with Nirgge Parduoc and is quickly pummelled. While fighting, Ōmaeda proceeds to attack but his attacks have no affect on Nirgge, who slaps him away sending Ōmaeda flying into the roof of a nearby building. Nirgge tells him he has no interest in fighting him and wished to fight Rangiku, calling Ōmaeda fat, Ōmaeda then comments back that Nirgge is fatter than him. Further berating the Arrancar as not understanding that his mass is a sign of his wealth, which is something that a poor person such as himself wouldn't comprehend. Nirgge then releases his Zanpakutō and begins to attack, Ōmaeda gets away narrowly. Ōmaeda quickly realizes with the new form and additional mass he is out classed in the battle with just the use of his sword. Nirgge continues to chase Ōmaeda taunting him all the while, until Ōmaeda tries to outsmart him by going up the side of a building believing that the Arrancar's weight will make it impossible to follow, stating that its not speed that wins in a city fight but cleverness. Ōmaeda is greatly surprised when Nirgge jumps the length of the building up to the roof and confronts him. When Nirgge proceeds to crush him with his trunk, Ōmaeda uses Shunpo to move behind the Arrancar to stand on his shoulders and holds his sword to Nirgge's head, much to the Arrancar's surprise. Ōmaeda gives his name and rank and tells Nirgge that he is Onmitsukidō and there is no way he is that slow. Nirgge becomes enraged that he has been made a fool of and goes to grab Ōmaeda, who moves out of the way using Shunpo to get above Nirgge while releasing his Zanpakutō's Shikai and delivers a heavy blow to Nirgge's head.
As Marechiyo taunts his apparently dead foe, the Arrancar ensnares Ōmaeda with his elephant-like trunk, and begins to stand up clearly annoyed. Nirgge proceeds to attack Ōmaeda when he is suddenly Suì-Fēng is thrown away by Ggio Vega's attacks and sent flying into the side of Nirgge's head, knocking him out. Ōmaeda goes to check on Suì-Fēng but she berates him for acting weak and tells him that he is never to turn his back on an enemy. Ōmaeda asks what kind of subordinate he would be if he didn't look after his captain if she is being defeated. He then resolves that they should fight Ggio together, Suì-Fēng dismisses the idea calling him a disgrace and goes back to fighting. Ōmaeda takes note that Ggio looks as though he is keeping up with her and wonders if they are truly evenly matched. He realizes that he should make an attempt to help, but realizes that Suì-Fēng would not welcome it so he decides to allow the even to play out as it will, he is then surprised attacked by Nirgge once again. Ōmaeda goes flying into a nearby building causing it to fall down on top of him. Nirgge gloats saying Ōmaeda got what he deserved, but is surprised when Ōmaeda frees himself from the rubble with only a few scratches on him. Nirgge goes to attack him again but Ōmaeda releases his Shikai and blocks the attack. He then follows up by spinning his Shikai as to deflect more of Nirgge's attacks. He then is caught up in paying to much attention to Suì-Fēng's fight with Ggio instead of his own, allowing Nirgge to wrap his trunk around his ankle and throw him around into nearby structures. Ōmaeda once again decides to help Suì-Fēng but realizes that first he must take out Nirgge, or risk getting attacked from behind. Nirgge begins to power up a Cero and draws Ōmaeda closer to attack him at point blank range, but Ōmaeda uses the momentum with his Shikai to propel himself forward even faster allowing him to crash full force into Nirgge's face knocking him out once again.
Shortly after when Ggio prepares to impale a trapped Suì-Fēng, Ōmaeda jumps in and blocks the attack with his Shikai. He then boldly grabs the Arrancar in a bear hug and tells his captain to attack. As Ggio prepares to blast Ōmaeda with a Cero, Suì-Fēng kicks him away, revealing she indeed had been feigning her loss in order to study the Arrancar's Resurrección. After knocking Ōmaeda back with a punch to the face, Suì-Fēng tells him if he sees an ally losing he should use the opportunity to attack the enemy from behind or stand aside if the foe is too strong, instead of stepping between them.
Suì-Fēng then tells him that his opponent is still alive as Nirgge begins to get up again. She then tells Ōmaeda to go and finish the Arrancar and then come and join her. Ōmaeda runs from an enraged Nirgge who continues to attack from a distance, Ōmaeda realizes he can't get close but he trips and falls. When Nirgge proceeds to land a devastating blow, Ōmaeda uses Shunpo and gets away, he appears up above the Arrancar once again. Ōmaeda states that he now understands Suì-Fēng's words, but takes it even further by addressing that opportunity doesn't only come when an ally falls but also when one is in a desperate situation. He then sends his Shikai flying down to crush Nirgge once and for all.
After Vega is defeated, Ōmaeda and Suì-Fēng prepare to battle Ggio's master, Baraggan Louisenbairn the Segunda Espada. Even with the assistance of his captain, the two of them are unable to move Barragan. Believing that Suì-Fēng is holding back because of the captain's seal, he begins bragging; but Suì-Fēng explains that the seal has not been placed on the captains this time and she is fighting at full power. Ōmaeda is shocked by this revelation. Barragan then takes out his Zanpakutō and begins to swing it at Ōmaeda and Suì-Fēng, who dodge the attack. Suì-Fēng tries to attack him with a kick but he grabs her leg and throws her into a nearby building, causing Ōmaeda to scream out to her. Suì-Fēng tells him that she is fine and not to worry about it. Ōmaeda listens as Barragan explains how he is able to counter the two and how the Espada represent the aspects of death.
He then witnesses as Barragan releases his Zanpakutō. When Suì-Fēng realizes what his power over old age can do after he breaks her left arm with a touch and then disintegrates the very building he walks on, Suì-Fēng screams to Ōmaeda to run as he is no match for Barragan. When Barragan uses his 'Respira' ability, Suì-Fēng commands Ōmaeda to withdraw, but when she is caught by it and her left arm begins to disintegrate, she has Ōmaeda somewhat reluctantly cut off her arm. Ōmaeda remarks to himself that he has seen a lot of guys but none of them compare to Barragan, noting that he thinks the Espada is even more dangerous than Aizen. As they can't get near him, much less touch him, Ōmaeda wonders how they can defeat him if they can't even attack him, but then he realizes the situation is worse than that, seeing that if he could get Suì-Fēng then no one can escape his attacks. Suì-Fēng then calls him to get his attention, she proceeds to tell him that she needs him to act as a decoy. Ōmaeda is somewhat confused, but Suì-Fēng assures him that all he has to do is keep him busy for a while as she has a plan. Ōmaeda becomes increasingly nervous and afraid stating to do anything would be impossible and no plan would work, as their only solution is to get away. Suì-Fēng tells him plainly to just make sure that he keeps his right arm, as he has to be able to cut of any parts that get turned to bone, she then leaves. Barragan then rushes at him, prompting Ōmaeda to run for his life so Suì-Fēng can execute her plan.
As Ōmaeda makes his get-away he notices an Ice Obelisk in the distance and wonders at what it is, then deduces it must be the doing of Captain Tōshirō Hitsugaya. He continues to run amongst the buildings, making sure to keep out of reach of Barragan. As the pursuit continues, Ōmaeda dodges yet another Respira, albeit a slow one, but it still manages to touch his captain's badge which he immediately cuts off. Ōmaeda begins to loose his resolve and doubting his survival in the battle, he then starts to scream for help.
Ōmaeda still acting as a decoy running from Barragan activates his Shikai and crushes a piece of building hoping that the fragments will hit and injure Barragan. When the pieces of rock disintegrate without even touching Barragan, Ōmaeda almost gives up realising how useless fighting him is and becomes frustrated that his Zanpakutō can't use fire or ice or some form of Kidō. Then he gets the idea that he can use Kidō as it most likely will get the better of Barragan. Ōmaeda turns and gets ready to take the offensive, but then he recalls he's not really good at Kidō and decides to simply use Bakudō #21. Sekienton, to create a smoke curtain to hide his escape. Coming to the conclusion that this was all the power his opponent had, Barragan calls forth his "Gran Caída" and seems to be closing in on Ōmaeda to finish him off with the technique. Barragan then notices the surge of energy from Suì-Fēng's Bankai being released and turns around to face her. Ōmaeda is surprised to see Suì-Fēng's Bankai as he himself has never seen it. He comments on its shape and wonders how she can fight with it. He then notices she has wrapped a Ginjōhan around her waist, wondering why she would use that as it decreases mobility. Ōmaeda then witnesses her explanation on why she doesn't use her Bankai and the explosion following its use against Barragan.  The resulting explosion sends Ōmaeda flying into the side of a nearby building at extreme force. As Suì-Fēng goes hurtling backwards as the Ginjōhan rips Ōmaeda catches her, he then notes that she defeated Barragan. Ōmaeda along with the rest of the standing Gotei 13 bear witness to the opening of a Garganta and the emergence of Wonderweiss Margera and a giant Hollow creature, much to his surprise. He once again stands in surprise as the smoke from the explosion caused by Suì-Fēng's Bankai clears to reveal a completely unscathed Barragan. Ōmaeda notes that it is impossible that Barragan could have survived it. He then witnesses the giant hollow creature blow out the fire imprisoning Aizen, Gin and Tōsen.
Shortly after the Visored arrive, Ōmaeda is noticeably amazed at their power as they take out hundreds of Gillian Menos with ease. Once all the Visored split up to face their opponents Hachigen Ushōda goes to aid Suì-Fēng and Ōmaeda in their battle against Baraggan. Hachi addresses Suì-Fēng, telling her it's been a long time since they last saw each other. Ōmaeda is somewhat surprised by this and asks her if she knows him and who he is. Suì-Fēng acts as if she does not know him, to which Hachi comments that he figured she would say as much, and that he is not surprised that she doesn't think well of the Visored.
After Hachi traps Baraggan in a barrier he persuades Suì-Fēng to use her Bankai to finish him which quickly depletes her spiritual power, causing her to fall out the air to the cityscape below. Ōmaeda screams to Suì-Fēng and goes to catch her. When Hachi asks if she is alright, Ōmaeda screams at him that of course she isn't, questioning what if she dies. Just then the building Suì-Fēng and Ōmaeda are standing on crumbles under them revealing an injured and enraged Barragan. He is later seen witnessing Baraggan's death.
When Ichigo Kurosaki returns from Hueco Mundo, Ōmaeda, along with the unoccupied Shinigami and Visored, prepares to protect Ichigo from Aizen and his Shikai. When Suì-Fēng charges at Aizen's position, he tells her to hold on a moment, but quickly follows her towards the ongoing battle.
Expert Swordsmanship Specialist: Ōmaeda is skilled enough in swordsmanship to hold his own in battle and in extension is also quite proficient using a flail. He was capable of fighting on equal ground with an Arrancar of lieutenant-level.
Shunpo Expert: Ōmaeda, being a member of the Onmitsukidō, is quite skilled with Shunpo.
Kidō Practitioner: As a lieutenant, Ōmaeda has enough of an understanding of Kidō spells to cast at least a Level 21 Kidō without its incantation. However, he admitted outright that he is not good at using Kidō.
Subterfuge Expert: Ōmaeda is thought to be inept and slow. It turns out he is quite fast as he is an expert in Shunpo as well as being proficient in combat, and mostly uses his clumsy and inept behaviour as a way to make his opponents underestimate him.
Gegetsuburi redirects here. For the manifested spirit that appears in the Zanpakutō Unknown Tales arc see Gegetsuburi (spirit).
Gegetsuburi (五形頭; Viz "Five Heads"; "Five-Formed Head"): It is a normal katana with a bright yellow handle and a brass octagonal-shaped guard with two square notches on opposite sides. Kept by his side through his waist tie.
Shikai: Its Shikai command is "Crush" (打っ潰せ, buttsubuse). In its Shikai, Gegetsuburi transforms into an oversized spiked ball attached to a long chain, similar to a flail, allowing for it to be thrown at a distant target. The chain is attached to the hilt of his sword. Gegetsuburi is a melee-type Zanpakutō, as Ōmaeda states it has no Kidō or elemental abilities.
Shikai Special Ability: Gegetsuburi has no special abilities to speak of though it is commonly used for long-range combat, Ōmaeda also uses it as a shield for close-range attacks. However, Gegetsuburi has proven to be a offensive weapon, rather than a defensive one, as it can be easily cracked, and even shattered, by stronger opponents. It is notable that against a Fracción like Ggio Vega, his Shikai cracks but does not break, while when against someone with captain-level spiritual power, such as Ichigo Kurosaki, it can shatter with one punch.
There is a slight inconsistency in the depiction of Gegetsuburi in both manga and anime depictions between its first and second appearance. When initially used against Ichigo Kurosaki, the Shikai appears to have much longer spiked protrusions, they were also silver. Yet by its second usage against Nirgge Parduoc and Ggio Vega, the spikes on Gegetsuburi are now smaller and less raised in form, becoming the same color as the rest of the ball.
When Ōmaeda's lieutenant badge was hit by Baraggan's Respira, he cut it off with his Zanpakutō. However, after Suì-Fēng's second Bankai attack on Barragan, it was shown that it was still on his arm.
Both Ōmaeda and Gegetsuburi's spirit are voiced by Shoto Kashii. When the two talk, it's essentailly Kashii talking to himself.