The Legend of Oppai Dragon and his Lively Companions[]
Bennia makes her first appearance in Volume 14 as one of Sona's newest additions to her peerage, alongside Loup Garou. Her sudden appearance surprised the other members of the Occult Research Club. She reveals that she left home because she didn't like the ways of Hades and her father. Originally, the Knight that Sona set her eyes on couldn't become Sona's servant, so she stepped in, in order to take their place. She wasn't seen as a threat or a spy of Hades because she is a big Oppai Dragon enthusiast. She even asked Issei for his autograph as an avid fan, showing him the many embroideries of Oppai Dragon on the back of her cape. She is later asked by Sona if she could accompany Loup with the task of backup of the outside area and leaves via magic circle, sinking through it rather than teleporting through the burst of light.
In Volume 15, Bennia accompanies Sona in her visit to the Hyoudou Residence. She said that the Oppai Dragon's residence is like a Shangri-La to her.
Bennia, Loup and Elmenhilde reunite with the others
In Volume 16, during the Vampire Civil War, Bennia, along with the Occult Research Club members and Loup Garou, went to Romania to aid Rias Gremory and Yuuto Kiba, who are confined in the Tepes' castle. After arriving in the territory of the Tepes' Faction, she and Loup went on their own way to secure escape routes. Bennia then assisted the Occult Research Club members on their plan to save Valerie Tepes and stop the extraction of her Longinus, Sephiroth Graal; battling enhanced vampires along the way. After returning from Romania, she and rest of the Student Council later participated in the meeting for the formation of D×D.
In Volume 17, Bennia helped in protecting the school her master Sona built against the mass-produced Evil Dragons, and was paired with Rias.
In Volume 18, Bennia and rest of the Student Council took part in the Christmas Project.
Bennia participated in the fight against the exorcists that rebelled against the Church in Volume 19. She was unable to fight normally as they were ordered not to take the lives of the exorcists so as to not increase the resentments of the exorcists any further.
In Volume 20, Bennia and the Sitri were sent on a mission to retrieve the city Agreas that had been found by the Team D×D, they were sent in first as a diversionary unit where they faced off against members of Qlippoth.
In Volume 21, during the Evil Dragon War, the entire Sitri team were sent to the Underworld in the Bael territory to stop a group of rebels led Bedeze Abaddon, who was trying to push the blame of the corruption of the Rating Game onto the Bael clan. Afterwards, Bennia and her teammates left to join the war against Qlippoth's army, led by Apophis whose in control of one of Trihexas bodies while on route to Japan.
Red Dragon Emperor of the Blazing Truth × White Dragon Emperor of the Morning Star: The True Dragon(s) of the Kuoh Academy[]
In Volume 22, Bennia becomes a student at Kuoh Academy and one of the newest members of the Occult Research Club. Le Fay and Bennia began to read about Youkai's living at the Kuoh Town, with Kunou whom had also enrolled offered her help on the subject.
Bennia was then among the rest of Sona's peerage who attended the opening ceremony for the Rating Game Tournament for the Azazel Cup.
In Volume DX.4, Bennia said that Saji was Sona's team's best option against Issei before the Rating Game match against Issei's team in Azazel Cup. During the Rating Game, she fought against Bova Tannin, as was able to dodge all of his attacking due to surpassing him in speed.
In Volume 24, Bennia was present at Kuoh Academy along with Millarca, Koneko, Ouryuu, and Gasper helping with Student Council work on cleaning the rubbish around the schools perimeter when a they were suddenly assaulted by a group of Grim Reapers. Both she and Ouryuu were able to escape and find Issei and Ravel to warn them of the present threat, they managed to make it back in time and save everyone, after which they suspected that the Reapers were actually after Koneko.
Under Sona's orders, Bennia stayed with the Gremory group believing to be more of help to them in this situation. They later contacted the Grim Reaper Orcas; her father for information, while they're informed that his group have nothing to do with Thanatos faction of Reapers that attacked them or his motives, Bennia still criticize him for not doing a thing about it.
When it came time for Rias' Rating Game match with Vali, everyone acted as guards outside the stadium. Bennia was joined with members of the Slash Dog and Red Dragon Emperor of the Blazing Truth teams when the Thanatos army arrived to capture Koneko and Kuroka, Lavinia took the lead in having frozen all of them in place, allowing the rest to easily strike them. Eventually their side was able to protect the Nekomata sisters and defeated the Grim Reapers.
Bennia reappeared in True Volume 3, participating in the meeting of the Occult Research Club about doing a program event for Kuoh Academy, with Bennia suggesting a popular Grim Reaper Cookies from the Netherworld.
In True Volume 4, Bennia decided to cooperate with the group going to England with plans to cooperate with the Grim Reapers said to be from the Moderate Faction for their battle against Hades. As the group arrived to England and discussing their strategy plan, Bennia revealed to the group about the information that she received from her father Orcus that Balberith being Hades’s guard and the traits of his and Verrine hasn’t been awakened. Bennia and Lint were instructed by Rias to be the bodyguard of Asia, Ravel and Ingvild, and shared a friendly interest with Lint due to their similar personalities.
When the battle began, Bennia opened the Grim Reaper gate that leads to the London’s underground of Hades’ territory. She informed everyone about Hades’ temple being other side of the flat ground and later in the final battle against Hades, she helped combined their power to weaken him, allowing Issei and Vali to deal the final blow. After the defeat of the Alliance of Hell, Bennia was officially promoted to Middle-class devil and she was traded to become a member of Issei’s peerage after Sona’s father succumbed to the sleep disease, forcing Sona to become the head of her clan now. Bennia and the members of Team DxD celebrated their victory at the garden of the Hyoudou Residence.