Aza Tōma (
Tōma is a young man with an androgynous appearance. He has long black hair and black eyes. He wears a dark haori and the standard attire of a Asaemon, which is a white robe with a bell tied on the left collar along with a hakama held together with a waist cord, and sandals.
Currently, Tōma's hair is now short after cutting it to show his dedication in wanting to become strong to Tamiya, and braided, mirroring that of his brothers. He also receives a small scar across the bridge of his nose and loses his funerary bell tied to his collar after trying to stop his brother from going berserk.
Tōma believes that the key to survival is adapting and views his brother as a prime example. He is very loyal to Chōbē and stresses out whenever harm comes to him. Unlike his brother, Tōma can be easily terrified by unexpecting situations. When they first encounter the Sōshin on the island, Tōma trembled in fear and panicked when they started speaking. Because he admires his strength, Tōma relies on his brother for protection, however, he is well aware that this will not always be the case and will have to use his own strength.
Because his father died rebelling with a group of allied samurai, Tōma has a hatred for cooperating with others, with the only exception being his brother. During his time serving his brother with a group of bandits, Tōma thought of them merely as pawns and used the Dōshi he and his brother captured as a slave. Tōma's loyalty towards Chōbē has led him to believe that he is more of like an extension of his brother rather than a comrade. Despite his disdain for alliances, Tōma is willing to work with others if it could lead him to reunite with his brother if they were to be separated.
When away from his brothers side, whenever someone would try to communicate with him, Tōma would respond with a threatening tone of voice while smiling. He also displays a rather cocky attitude. After withstanding the Tao lessons Gabimaru and Yuzuriha instructed, Tōma smiled thinking that he has surpass Tamiya after seeing him heavily exhausted from the training.
Tōma and Chōbē were born as sons to a retainer under the service of the daimyō of Akō Domain, Asano Takunori. However, after Asano Takunori attacked the court official Kira Yoshinaka at Edo Castle, he was sentenced to commit seppuku. As a result, their father and the rest of the retainers had their status removed and were left as rōnin, leaving their family in poverty. Their mother eventually died of an illness and their father was executed for being a part of the Akō Incident, leaving the two siblings left alone to defend for themselves. They were eventually taken by bandits who planned on selling them but later came to live amongst them after Chōbē managed to become their leader.
During their years as bandits, Tōma and Chōbē were cornered and were about to be arrested. Chōbē tells Tōma to escape and trusts that he would come and rescue him from prison. After infiltrating the Yamada Clan and rising to their ranks in a month, Tōma was given a chance to take on an execution. He then comes to free Chōbē in prison by presenting him the mission given by the shogun to find the Elixir of Life.
After Chōbē became one of the few that survived the massacred order by the shogun, Tōma was assigned to be his Asaemon and they departed to the island.
Before arriving on the island, Tōma watched as Chōbē was being strangled by Hōrubō but managed to break out and kill him. His Asaemon, Yamada Asaemon Jikka, then thanked him in gratitude and returned to the main land. Once they arrived on the island, the two were approached by monsters and fight them off. Later, the monsters started to speak and Tōma became fearful of them. Hearing them speak of sin, Chōbē unleashes his rage on them and slaughters them while Tōma watched in admiration. Chōbē declares that he will kill all of the criminals on the island and they will claim the elixir for themselves. Tōma smiles and makes a statement to Chōbē, saying that only the strong will survive the dangers of the island while the weak will not.
During the next day, the two brothers continue to slaughter the monsters in their path. Tōma sees Chōbē drinking the monsters body fluids to keep himself hydrated, commenting on how he is adapting too well. After Chōbē asked about the Hermits mentioned earlier, Tōma describes them as immortal, superhuman old men who possessed magic, however, Chōbē wasn't convinced but declares that he will kill them if he were to come across them. The brothers then discover two females sitting on top of ruins having sexual intimacy. Chōbē becomes frighten by one of them and sees them as monsters. The first woman asked if they wanted to join, much to their confusion, while the second turns herself into a man and says that he will kill them, causing Tōma and Chōbē to go on guard. They are then defeated by the man.
Lord Tensen Arc
After their defeat, Tōma and Chōbē were dropped down a pit of blooming human corpses. Tōma gazes in horror and finds his brother entangle in vines. He rushes to his aid but is also entangle by the vines. Chōbē later escapes along with Tōma on his back by climbing his way up. Tōma suggests leaving the island and tending to their wounds but Chōbē vows revenge on the two. He recommends devising a strategy but Chōbē says that he had already figured out their weakness. Chōbē then offers him a severed limb from the pit for nourishment but turns it down. While talking they are approached by a monster called a Dōshi who politely ask them to return to the pit. Chōbē refuses and engages in battle. The Dōshi becomes furious with his behavior and summons the Sōshin to attack. Tōma is ordered by Chōbē to fight the Sōshin while he handles fighting the Dōshi.
After the Dōshi ends their battle by ripping out Chōbē's throat, Tōma screams in horror and rushes to his aid but sees that Chōbē wakes up with his neck fully healed. Chōbē then asked Tōma why he wasn't fighting the Sōshin which caused Tōma to apology and continues where he left off. While fighting, he worries over Chōbē's condition. After the Dōshi receives damage from Chōbē, he tries to call forth the Sōshin but Tōma smiles stating that he had already killed them, allowing Chōbē to end their fight. Tōma notices that the markings on Chōbē were beginning to spread. He then gives him a frightening gaze and asked Tōma if there was anything wrong. Tōma tells him that there was nothing wrong and apologies. This scene starts to make Tōma become even more worried.
The next day, Chōbē and Tōma has the injured Dōshi guide them to Hōrai where they stumble upon Gabimaru, Tamiya, Fuchi, and Mei. Chōbē attacks Gabimaru while Tōma is ordered to fight the other three. Tōma attacks Tamiya first since he sees that he is missing his left hand. However, Tamiya catches and his blade and easily strikes him down. Tamiya becomes furious with Tōma that he attacked him first because of his handicap and demands that he picks up his sword so they can begin fighting.
Tōma is unable to land an attack on Tamiya and takes on direct blows. He is then criticized by Tamiya on his lack of battle experience because of how he resorts to relying on his brother and how it would have been a wise choice to team up with his party. Tōma expresses his hatred for alliances and tells him how he is only an extension of his brother. After adjusting the grip on his blade, he orders the Dōshi to attack Fuchi and Mei. Tōma then suddenly watches in fear as Chōbē transforms into a demonic form to fight Gabimaru. Remembering what Tamiya told him about Chōbē fighting to protect him, Tōma rushes to try to save him from losing his sense of self and ends up getting attacked. The brothers are then caught in a massive crater created by Mei trying to stop Gabimaru from ending his life with his next attack. Chōbē pushes Tōma out of the way and tells him to wait for him. He is then hit by rocks thrown by Gabimaru, causing him to fall down the valley.
Tōma falls into despair and is forced to accompany the group traveling to the Hōrai gate where they meet Sagiri, Shion, Yuzuriha, Nurugai and Hōko. The group then relocates to a cave to hide from Lord Tensen. Tōma follows Shion, Tamiya and Nurugai who are called out by Gabimaru to help him train. Gabimaru insists that Tōma uses his hatred towards him to take revenge for his brother. After being given Tamiya's sword, Tōma rushes in to strike. Gabimaru senses the movements of Tōma's Tao and dodges his attacks. Later, after finishing their sparring, Tōma begs Tamiya to teach him how to wield a sword and shows his resolve by cutting off his hair. Tamiya agrees to teach him and moves to another spot to train in private. While following him, Tōma states to himself that he sets on becoming strong so that he can fight equally alongside his brother and hopes that he waits for his return.
Later, Tōma thanks Fuchi for treating his nose injure but has his gratitude rejected by the Asaemon. The group is then warned by Mei that someone or another group has arrived on the island. Shion and Fuchi believe that it is Shugen and the other Asaemon who were sent as reinforcements by Eizen, along with another group of criminals. Although Sagiri vouched for his cooperation, Shion denies this after explaining the full story of the Silver Serpent's group execution and how he does not cooperate with criminals or allow any Asaemon to work with them as well. Moving on, Shion presents his strategy of finding the Tan elixir and an escape route by separating everyone into two teams and using their Tao attributes to hinder and defeat each member of Lord Tensen. However, Yuzuriha suggests finding a way off the island and go into hiding. Shion takes her recommendation into account and gives everyone the option of working separately or working together in completing the mission. Unanimously, everyone decides to follow Shion into the cave and work together for their own personal reasons.
Palace Invasion Arc
Using the information Mei provided, the group strategies on how to escape the island by using the ships located within the palace and learns that the elixir is located in Rien's laboratory. Shion then pulls Gabimaru and Yuzuriha over to have them instruct the group on espionage using Tao. After the lessons were over, Tōma sees Tamiya exhausted from the training and comments on how he might have become stronger than him, which irritates the swordsman and challenges him to a fight. Tōma is then placed in the Escape-Route Team along with Tamiya, Shion, Fuchi, Nurugai, and Mei. Tamiya suggests that they should have Mei depart alone without having to wait for the Elixir Retrieval Team since she wishes to leave the island. However, after Mei confesses to everyone that she wants to reunite with Rien and Xu Fu to ask them why they underwent a major in the past before leaving, Gabimaru promises to fulfill her wish. After reviewing their strategy to infiltrate the palace, the group decides to make their move tonight.
The Elixir Retrieval Team sneaks into the palace and signals the Escape Route Securing Team that it is okay to enter. The team advances into the palace but are met by a sudden mist, causing Tōma, Tamiya, and Fuchi to get separated from Shion and Nurugai. The three then encounter Tao Fa and Ju Fa who plan to offer them as sacrifices to the grandmaster. Knowing that their plan to avoid Lord Tensen has failed, the group moves on to their second plan of fighting against them. Tōma then reunites with Chōbē and is allowed by Tamiya and Fuchi to be by his side without worrying about him being their enemy. After walking upstairs to join his brothers, the two smile and attack Ju Fa and Tao Fa. Chōbē comments that Tōma became slow but the latter objected saying that he knew that his undone braid signaled that what he was saying before was a lie. Chōbē corrects him saying that he meant that he was talking about his movements but then retracts his statement and says that he is impressed with Tōma's new improved skills. The Aza Brothers fight against Ju Fa after he has fully healed and manage to gain the upper hand with their new skillsets. Tōma sees Chōbē about to enter his transformation but stops him with full confidence that they can defeat Ju Fa. However, they see Ju Fa reaching out to grab a transformed Tao Fa's hand and fuse together, resulting in activation of their Kishikai.
Chōbē prepares to jump in to attack the fused Tensens. Tōma tries to stop him but is told by his older brother not to. Chōbē commences his attack but is quickly defeated, causing Tōma to panic. Tōma then defends his brother after Chōbē and Tamiya start to insult each other after Fuchi suggests that they should team up. Ultimately, the brothers agree to cooperate after Fuchi brings up the point that the monster is their main target. While Tōma argues to Tamiya and Fuchi that they need to follow his brothers orders, the three are about to be attacked by the monster but are protected by Chōbē. Tōma then comes in to cut one of the vines that was about to attack Chōbē and grabs Fuchi's hand to use their idea of strengthening the Asaemon's Metal Tao to harm Tao Fa. Tamiya jumps in to attack but cause the monster to flee in the air. Tōma complains to Tamiya for his actions but is warned by Chōbē that the monsters form has changed. He then places Tōma and Fuchi together to take down Tao Fa while he partners with Tamiya to attack Ju Fa. Tōma asks his brother what he should do but is hit in the head by Chōbē, telling him to think for himself and that he has faith in his abilities.
The four fend off against the monsters vine attacks. Tamiya rushes cutting away at the vines to give Tōma and Fuchi an opening to attack. Tōma senses the monsters spore attack aimed at Fuchi and protects him with his own body, reasoning being that his Tao is important in his brothers strategy. After Tamiya enters the pool and slices through the Kishikai body from the bottom, Tōma senses Tao Fa located at the bottom right and relays the information on to Fuchi to attack. Fuchi and Chōbē deliver the final strike to the two Tensen's tanden and end their Kishikai state. As Chōbē pours Water Tao from a bottle he had on hand to stop Ju Fa from regenerating, Fuchi finds this action to be in poor taste to which Tōma explains that his brother always maintained the role of the villain.
Abilities and Powers
Despite not being an official Asaemon, Tōma was trusted to take on the shogun's life risking mission, testifying to his abilities. He was strong enough to easily kill multiple Sōshin, who were trusted by Lord Tensen to eliminate any trespassers, and soon became one of the first few in 1,000 years to have managed to survive the ordeals the island had to offer and reach Hōrai where Lord Tensen currently resides. After training under Tamiya and undergoing Tao lessons, Chōbē and Ju Fa noted that Tōma's skills has improved considerably, being able to keep up with his brother in fighting the Tensen and deal damage, which he was unable to do the first time they fought, and was able to handle the Tao lessons taught by Gabimaru and Yuzuriha, which Tamiya, the one who improved his swordsmanship, could not endure.
Tōma is very talented with the sword, being credited as the fastest member in the Yamada Dojo to earn his license after only a month and easily massacred the Sōshin without any aid. With the skills he gained from the Yamada clan, Tōma is capable of decapitating his target with a single cut of his sword.
After training under Tamiya to improve his skills, Tōma's swordsmanship has become a lot higher than it was before, being taught to face danger head on and strike. This was shown as he managed to land a critical hit on Ju Fa during their rematch.
- Further information: Tao
Tōma possesses Earth-attributed Tao. After learning how to awaken and use it by Gabimaru and Yuzuriha, Tōma is capable of sensing the Tao around him.
- Tōma ranked 12th place in the manga 1st Character Popularity Poll.
- Though he is recognized as being a Yamada Asaemon on the mission, Tōma has yet to carry out an execution, which is a requirement for a member of the Yamada clan to earn their name.