Yuuto Kiba/Plots

The Red Dragon Emperor's Awakening
Yuuto made his appearance in Volume 1, bringing Issei Hyoudou to the Occult Research Club under Rias' orders. He later assisted Issei in his attempt to save Asia Argento from the Fallen Angel Raynare.

In Volume 2, after the announcement of the Rating Game match between his master and her fiancé, Riser Phenex, Yuuto accompanied his allies to a training camp in the mountain for a week. He later participated in the Rating Game where he successfully defeated Riser's three Pawns: Shuriya, Marion, and Bürent before being eliminated by Riser's Queen, Yubelluna. He was then seen attending Rias' engagement party where he helped Issei fend off the security to open up a path for his new friend.

Birth of the Breast Dragon Emperor
In Volume 3, Yuuto's past came back to haunt him again after seeing Issei's photo as a child with Irina Shidou and her father who is holding a Holy Sword. This only got worse after the appearance of Irina and Xenovia Quarta who were ordered to retrieve the stolen Excalibur swords. Issei eventually manages to make a temporary alliance with the Church duo, where they will help the two of them retrieve the Excaliburs in return for giving Yuuto a chance to let go of his past and move on by destroying the Holy Sword once and for all. This also allowed Yuuto to learn of the person in charge of the Holy Sword Project, Valper Galilei. The team was eventually attacked by Freed Sellzen and Valper which causes Yuuto to chase after them. Yuuto later returns to help his friends in their fight against the Fallen Angel Leader Kokabiel, Freed, and Valper. He eventually learns the truth behind the Holy Sword Project, and with the help of his friends' spirits from the light-attribute crystal, Yuuto was able to achieve his Balance Breaker, the Sword of Betrayer. He, then, goes on to break the stolen Excalibur with the help of Xenovia. The Occult Research Club was then confronted by Kokabiel and was overwhelmed by the latter until the intervention of Vali Lucifer who came to retrieve Kokabiel under Azazel's orders.

In Volume 4, during the meeting between the leaders of the Three Factions which was interrupted by the sudden attack from the Khaos Brigade's Old Satan Faction leader, Katerea Leviathan, Yuuto assisted in fighting off the magicians from the Khaos Brigade along with Xenovia. Yuuto also gave a Holy Demonic Sword to the Archangel Michael in exchange for not allowing any Holy Sword research facility to produce more victims.

In Volume 5, Yuuto, like the rest of Rias' peerage, returned to the Underworld for the Young Devils Gathering. In the Underworld, Yuuto trained in maintaining and using his Balance Breaker for long fights. During the Rating Game between his master and Sona Sitri, he and Xenovia faced off against Tsubaki Shinra, Tomoe Meguri, and Tsubasa Yura. Yuuto was able to defeat Tomoe and Tsubasa by using the new technique formed by him and Xenovia, "Durandal Birth", which combines the holy aura of Durandal and the holy-demonic swords that sprung forth from the ground. Near the end of the match, he chased after Tsubaki but was temporarily interrupted by Akeno before going on to eventually defeat Tsubaki.

In Volume 6, during Rias and Diodora Astaroth's Rating Game that was interrupted by the Khaos Brigade, Yuuto fought Freed Sellzen, who had turned into a Chimera, easily cutting his body to pieces before destroying his head, killing the latter. He later shielded the members of the Gremory group with multiple holy-demonic swords from the impact of the Longinus Smasher. He, along with the rest of the Gremory Team, was last seen cheering for Issei and Asia on their three-legged race.

The Heroic Oppai Dragon
In Volume 7, after fending off the Sacred Gear users and anti-monsters sent by the Hero Faction of Khaos Brigade, Yuuto tagged along with Rias, Asia, and Gasper to spy on Issei and Akeno's date, but soon lost them when Issei and Akeno escaped. The Occult Research Club was then asked to serve as Odin's bodyguard as they are attacked by the Norse Evil God Loki and Loki's son, Fenrir. The Occult Research Club, along with Baraqiel, Rossweisse, and Saji, later teamed up with the Vali Team to fight their final battle against Loki and Fenrir.

In Volume 9, during his trip to Kyoto with the second year students of the Occult Research Club, the team crossed path with Khaos Brigade's Hero Faction after the latter kidnapped the leader of the Youkais, Yasaka. In the battle to rescue Yasaka, Yuuto and Xenovia fought against Siegfried but were easily defeated by him.

In Volume 10, after being defeated by Siegfried, Yuuto trained to achieved the Balance Breaker of Blade Blacksmith which he reveals in his fight against Beruka Furcas during Rias and Sairaorg Bael's Rating Game. Yuuto, Rossweisse, and Xenovia then faces Sairaorg in a three-on-one battle but lost to the latter (although they managed to cut off one of Sairaorg's arms).

In Volume 11, Yuuto received a promotion recommendation along with Akeno and Issei. While the group was resting after the test, they were ambushed by Cao Cao and Georg who came to steal Ophis' powers. The battle ended with the Gremory and Vali Teams losing to Cao Cao and Ophis' powers getting stolen. Both teams were then attacked by a legion of Grim Reapers and Siegfried. He, then, has his rematch with Siegfried, which ended with Yuuto cutting off one of Siegfried's Dragon Arms. Like the other members of the Gremory Team, Yuuto was shocked to learn that Issei had "died" at the end of Volume 11.

At the beginning of Volume 12, Yuuto and the other members of the Gremory Team stayed in the Gremory Palace, while the whole team was still in shock with Issei's death, especially Rias and Akeno. Yuuto later goes to the basement of the Gremory Palace to check on the Vali Team while asking the original Sun Wukong about Samael's curse. The Gremory Team later goes to the Human world to ask the creator of the Evil Pieces, Ajuka Beelzebub, to check on Issei's Evil Pieces and was surprised to see the Old Satan Faction and Siegfried who had come to offer an alliance with Ajuka. He, then, faces off once more against Siegfried in their third and final encounter. During the fight, Siegfried uses Chaos Break which makes his body undergo a demonification process to transform into a monstrous spider all while fusing with his Demon Swords and Sacred Gear. With this new form, Siegfried easily overwhelms all the members of the Gremory Team, cutting off Yuuto's left arm (which he was able to reconnect later in the battle through the combined efforts of Ravel, Koneko, and Asia) and injuring both of his legs. The battle was overturned when one of Issei's Evil Pieces transformed into the sword Ascalon, allowing Yuuto to injure Siegfried. Siegfried finally lost to the latter after his strongest Demon Sword, Gram, left him and chose Yuuto as its new wielder. As he received attacks from the Gremory Team with Yuuto dealing the final blow by stabbing him with both Gram and Ascalon, his body started to crumble away. After the battle, Siegfried's remaining Demon Swords chose Yuuto as their new wielder. After Cao Cao's defeat, Arthur challenged Yuuto after deeming him to be a worthy opponent for his Holy King Sword, telling Yuuto that he will fight him when Vali fights Issei, which he quietly accepts. At the end of the same volume, Yuuto is also officially promoted into a Middle-Class Devil.

The Legend of Oppai Dragon and his Lively Companions
In Volume 14, Yuuto is shown to be training Xenovia on how to better use her Ex-Durandal, claiming that should Xenovia master all seven abilities of the Excalibur in addition to the Durandal, she would surpass him as a swordsman. He later goes to Romania along with Rias and Azazel in order to find out more about Gasper's unknown power.

In Volume 15, Yuuto accompanies Rias who was staying at the House of Vladi until a Vampire from the House of Tepes asked them to meet the current leader of the Tepes Faction, Valerie Tepes, much to the surprise of the two.

In Volume 16, Yuuto and Rias reunited with their friends who came to the Tepes territory. He later participated in rescuing Valerie from Marius Tepes who attempted to extract the Longinus, Sephiroth Graal, from Valerie where he and his friends fought against the modified Vampires and Grendel. After Rizevim turns all of the modified Vampires into mass-produced Evil Dragons, Yuuto and Rossweisse teamed up together to fend off the mass-produced Evil Dragons. After returning to Japan, Yuuto participated in the meeting for the formation of D×D.

Yuuto, along with the other members of the Occult Research Club, went to the Underworld in Volume 17 and participated in the experience day for the school Sona Sitri built located at Auros in the Agares territory. While doing the respective activities assigned to them, Qlippoth managed to surround both Auros and Agreas inside a barrier and announced their intent to attack after a certain period of time. Before the time was up, they reconfirmed their plan and Yuuto ended up pairing with Tsubaki of the Sitri group and fought against the mass-produced Evil Dragons.

Yuuto and the Occult Research Club went to Heaven in Volume 18 to talk to Michael about the Christmas project the alliance is working on. After the meeting, Michael informed them about the death of Church officials and the presence of Evil Dragons were present. Yuuto helped defend Heaven from the attack of Qlippoth. He, along with Rias, Koneko, Gasper, Akeno, Rossweisse, and Cao Cao, fought against the Evil Dragon Ladon and three of Grendel's clones. He was able to successfully defeat a clone with the help of Rossweisse and Akeno. After all the fights were settled, Yuuto and the Occult Research Club celebrated Christmas and it was announced that he will succeed Akeno as the new Vice-President of the club.

In Volume 19, Yuuto participated in the fight against the exorcists that rebelled against the Church. He requested to transfer to the group that would fight against Ewald Cristaldi saying that he doesn't want to fight against him for revenge but as a challenge against the former wielder of Excalibur. Before the fight, Issei reminded him not to take his life for granted and that he should return alive. Struggled in the fight against Ewald after being dosed with enhanced Holy Water, Yuuto almost wielded Gram risking his life-span being devoured by the Demonic Sword, but was stopped by Dulio Gesualdo, saying to save that against Qlippoth and hugged Yuuto, seeing him as his brother since he also came from one of the Church facilities. Dulio used his technique, Speranza Bolla di Sapone, that made Yuuto remember the things important to him. Because of this, Yuuto was able to use a new technique, siphoning the holy aura of the opposing holy sword, and was able to defeat Ewald with the combined efforts of Irina, Dulio and Griselda Quarta. After the fight against Ewald, he and Irina transferred over to the field where the Gremory team, Saji, and Arthur was fighting against the group led by Vasco Strada. Yuuto attacked Vasco but the latter was able to easily block Yuuto's sword and crush it his bare hands. After the fight against Strada, Walburga appeared and fought against them and was defeated with their combined efforts. Before Vasco was taken away for interrogation, he introduced a girl from Yuuto's past, Tosca. Yuuto was overjoyed with their reunion and hugged each other while crying. Vasco told Yuuto that she survived the Holy Sword Project because of her Sacred Gear and he wants for Yuuto to take care of her.

In Volume 20, everyone in Yuuto's year was having a career consultation with the Gremory servant attending the meeting with his teacher. Along with members of D×D, they met up with Ajuka, after having recovered Ravel, reveals to them the truth about his secret invention known as the King Pieces. When they discovered the location of Agreas, where the hideout of Qlippoth was based, Yuuto and his friends infiltrated the stolen city. The Gremory group face off against the Evil Dragon that kidnapped Issei's Parents; Niðhöggr. While they had difficulty in beating him due to the Evil Dragon's use of Phoenix Tears, they are saved when Crom Cruach shows up and starts beating Niðhöggr senselessly. Yuuto, later, assisted Issei and Asia to find their parents by clearing a path through an army of Evil Dragons fighting alongside Irina and Xenovia.

In Volume 21, days after Trihexa had been unleashed and wrecking havoc onto the world, Yuuto and his friends joined an army on an island on the coastal waters of Japan to battle Qlippoth's army of Evil Dragons, fake Scale Mails and one of Trihexa's bodies controlled by Apophis.

In Volume 22, some time after completing their end of semester tests, Yuuto and the rest were later seen the club preparing it for the new semester he hands the new president Asia documents for the new school year. They reminisce over the past year and how far they've come in contrast to recent events, Yuuto also tells Issei that his friend Tosca will be enrolling in the school and be coming over to the club room after school. They then discuss plans they have for the future, Yuuto in particular plans on saving enough money while working for Rias to open up a cake shop in town after graduating high school. Next weekend, the Gremory group, Vali's team, and Issei's parents went on a fishing trip on an inhabited island owned by someone related to them. During which, Yuuto was with Tosca, showing her the sea whom the young girls were delighted to see a vast amount of water for the first time.

He and all of Issei's friends were present during his promotion to a High-Class Devil and later after the graduation ceremony, Yuuto was now able to refer to Rias as "Rias-neesan", this however made Akeno a bit jealous as she also wanted them to refer to her as such, Yuuto then assured her with a troubled look that they will someday. Soon afterward, he and everyone witnessed Issei proposing to Rias.

Red Dragon Emperor of the Blazing Truth × White Dragon Emperor of the Morning Star: The True Dragon(s) of the Kuoh Academy
Yuuto and all the members of Rias' team attended the opening ceremony of the Azazel Cup and witnessed Issei and his team's grand yet late entrance while over Ryuuteimaru flying.

In Volume 23, Yuuto and his team had won continues victories over the course of the tournament, when they then faced an Ultimate-Class Devil on their next match, he had defeated the opposing teams Knight in the blink of an eye. Soon enough Rias' had won yet again when the Ultimate-Class Devil had to surrender the match.

Yuuto and his friends were in the spectator room for related personnel observing Issei's Rating Game with Dulio, Rudiger was also present and discussed with Rias the strategies he thought of to be used against Issei. Long after the game had ended, Yuuto and the ORC members participated in their school's Ball tournament where they play Basket Ball against the Student Council led by Xenovia, in the end however the game ended in a draw.

In Volume DX.4, Yuuto participated in the Oppai Dragon Show as Darkness Knight Fang who became an ally of Oppai Dragon and facing their new enemy Bova who is Evil Dragon General Vabo. They were aided by Sairaorg, who is playing as Leonis Rex, and together they defeated Vabo. Yuuto and the current and former members of the Occult Research Club went to the Agares territory to watch the match between Sairaorg and Cao Cao, with Cao Cao emerges as victor due to having more points. A few days later after the previous match, Yuuto and his team went to the Armaros Colosseum in the fallen angel’s territory to watch the match between Issei and Sona with Issei becomes victorious after Xenovia defeated Sona in a single battle.

In Volume 24, The entirety of the ORC and Hyoudou Residences came to the school pool for a relaxing time, Yuuto was primarily quietly swimming by himself, switching his form From freestyle to butterfly and blissfully swam on his own. They all headed back to Issei's when they heard that most of everyone else's parents had paid a visit. Upon arrival, they learned the reason for their meeting was to discuss plans for the wedding ceremonies for each of Issei's fiancées. Yuuto told Issei that there'll be plenty of VIPs at his weddings so it was crucial to plan these things. Vasco who was also present revealed to have joined Rias' team, he would also train Yuuto to further improve his swordsmanship.

Eventually, everyone heard word of Grim Reapers who came after Koneko, they found out the Reapers lead by Thanatos was after Koneko and her sister due to their late father had done experimental research on artificially creating Super Devils, leaving everyone to protect the two girls under any means.

When the time came for the Gremory and Vali Teams to face each other in the next match, initially stood and watched the addition to their group; Vasco single-handedly outmatched Vali, Bikou, Fenrir, Gogmagog. When Arthur decided to face the old man one-on-one, which then Bikou choose to fight Yuuto. Throughout their fight, Yuuto created his army of Dragon Knights to counter Bikou's clones while the two real ones clashed with each other with Gram and Ruyi Bang respectively as they exchanged blows with a speed that was so fast that it was not visible to the naked eye. Due to his training with Vasco, the way that Yuuto he used Gram in a close-range fight had changed, for he had learned to release a vast amount of aura in the instant of the sword’s impact in order to compensate for his lack of power. This method pressured Bikou to step back attack with his Ruyi Bang extending at him, but Yuuto's lighting fast speed was able to dodge and appear behind him to strike him.

Eventually, Bikou’s Ruyi Bang was cut apart but he pulled a second one from his ear. Yuuto responded by vanishing his Dragon Knights to use his other Sacred Gear to summon a horde of Holy-Demonic blades from the ground which forced Bikou to jump, thus creating an opening for Kiba to finish him with Gram coated in Holy-Demonic aura. Later, however, Yuuto and his team had lost when Rias had to forfeit the game.

In Volume 25, Yuuto notice the rumors about Rossweisse’s condition in Kuoh Academy and warned Issei not to charge to Asgard recklessly, and he might damage the relationship between the Underworld and Asgard because he is angry which Issei pointed out that he isn’t angry but Yuuto tells him that he has a bitter expression whenever he thinks about Rossweisse. He joined his team and Issei’s team in the smartphone game called Belzebut for their training held by Ajuka. During their break from training and Akeno handing everyone food, Kiba noticed that he was feeling hungry and after eating her onigiri, he apologized to Issei in his thoughts. Yuuto and his team travel to Valhalla to cheer for Issei and his team in their match.

Yuuto and his team celebrated at the Hyoudou Residence for passing the preliminaries along with the rival teams. When Issei’s rival started to talk to Issei, Yuuto joined in and wishes to fight Issei in the main stage of the tournament.

Yuuto reappeared in True Volume 1, Arriving at the park where Issei was attacked by the unknown devils and transported them to the Underworld. He and the group arrived at the town where the devils were residing, Yuuto and Xenovia together cut down some of them with their respective swords Holy Demonic and Durandal. When a purple-haired girl started to sing that causes pain to Issei, Ddraig, and Bova, Yuuto and Xenovia held their weapons against her until they were stopped by Issei. Like the others, Yuuto became astonished to learn from Ajuka that the girl is Ingvild Leviathan, a descendant of Leviathan and a half-Longinus wielder and when she awoke from her sleep, he and the group took her to the beach on an unpopulated island with Rossweisse placing a barrier until their fun was interrupted by the arrival of the goddess Nyx. After reporting to Ajuka about Nyx’s actions and gaining the approval from Apollon, Yuuto spoke with Cao Cao regarding Nyx’s Godly Virgin Killer Clothes who consider it a bluff to block Issei’s dragon powers, Yuuto joins Issei and the others to travel to Nyx’s location. Heading to Nyx’s location, Yuuto and the group came across the devils and he and the sword group remain behind until they assisted by Cao Cao and Vasco.

After Nyx was defeated, Yuuto and his team traveled to the Agares territory for the tournament announcing the next matches and learned they will be facing Issei and his team in the first match. Yuuto challenges Issei for battle as he would become his enemy as Rias’s knight with later Xenovia challenging him as knights.