Memory Loss Arc

The Memory Loss arc is the sixth story arc in the Beelzebub series, taking place during Chapters 139-142 of the Manga. This arc is an immediate follow-up to the previous one, the Akumano Academy Arc. It details Hilda after she lost her memories and is now with a completely different personality.

Synopsis
Spoiler warning: Plot and/or ending details follow.

Amnesiac Awakening
The next day, Oga finds Hilda awake in his room, changing into her usual clothes. He expresses his relief that she appears normal and tells her not to worry Baby Beel to much. However, Hilda asks where she is and proceeds to ask the same thing of Oga. As Oga and Baby Beel stand speechless, Hilda continues on by saying how she doesn't know why she decided to dress up in her usual clothes and that she doesn't even know her own name. She doesn't even recognize Baby Beel, upsetting the Demon Lord.

Hilda is brought downstairs and Oga's family are then told that she has amnesia. His family is shocked but even so, they try to take care of the situation by reintroducing themselves to Hilda. After listening to them, Hilda asks if she's a part of their family. This causes everyone, except Oga and Baby Beel, to be driven to tears. Misaki, from her point of view, retells Hilda's past to her and even explains that she's Oga's "wife". Hilda is clearly shocked and embarrassed, even though she still doesn't understand what a wife is. Oga's Mother decides to teach Hilda more about being an actual wife, starting off by showing Hilda some soap operas. Hilda starts to understand more about being married to Oga and calls him by his first name, Tatsumi. She then gets to hold Baby Beel, her "son". Hilda becomes very affectionate to Baby Beel and treats him endearingly as though he really is her child. While everyone is touched, Oga is clearly not in the mood to speak. He remains sullen to the end of the night and starts distancing himself from Hilda. Oga states that he can't do anything about it, however, as everyone else including Baby Beel is happy about the new Hilda. He then falls asleep but awakens in the middle of the night. He finds Hilda and Baby Beel sleeping next to him, causing him to scream and ask why Hilda is even in his bed. Hilda asks if her actions were inappropriate and wonders what Oga doesn't like about her, since they are "married". Oga cannot handle the situation and runs away from the house with Baby Beel.

He eventually returns by morning to get dressed for school, though he and Baby Beel are sick from being outside in the cold night. Hilda starts taking care of him and Baby Beel. She remains oblivious about Baby Beel being a Demon Lord and argues with Oga when he tries to explain things. She eventually gets clothes for Baby Beel and a scarf for Oga. Afterwards, she accompanies him to school.

As they walk, the meet Furuichi and Oga explains more about Hilda's situation with him. Furuichi tries reintroducing himself to Hilda but instead of saying something friendlier, she calls him a pedophile and "Creepichi" much to his disdain. Oga says that he retold Hilda about certain events from the past and this angers Furuichi who then tries clearing his name to the Demon Maid. Hilda replies by saying that she simply thinks of Furuichi as a 'creepy douche' by natural instinct. Oga then starts thinking that Hilda's memories may return if he just introduces her to familiar people, like Furuichi. He has the two run to the school with him.

Back to Saint Ishiyama Academy
At the Ishiyama homeroom at their school, Oga explains about Hilda's amnesia to the Red Tail. Though surprised, the girls were actually more interested in a betting pool they made earlier: it was to determine Hilda's first words upon waking up after Oga saved her. The girls then start talking about how little they did during the Akumano Academy invasion. Hilda still can't remember anything but questions if Oga did something that required him to save her. He claims he doesn't know anything.

Nene Ōmori hears everything from outside the room and notices Aoi approaching the room. She starts worrying about how Aoi will react when she finds out about Hilda's amnesia and distracts her. Nene takes a reluctant Aoi to the restroom.

Hilda is then brought to Kanzaki and Himekawa but even after beating them up (at Oga's insistence) she still can't remember a thing. They visit the regular Saint Ishiyama students including the Rokkisei, but their plan is no better than when it first began. After encountering several other people that Oga knows, ranging from other Ishiyama students to various teachers, it becomes clear that restoring Hilda's memories is almost pointless.

Oga and the others then head to the school rooftop. Hilda tells Oga that she notices that he's well-acquainted with a number of people. He denies this and starts walking away. Hilda then asks if it's really important that she regains her memories. She adds that while she does want to know more about her past, she doesn't want to forget and lose the happiness that she's currently feeling. Oga then tells her that she has to be a violent-type of woman, as that's who she is. This intimidates her and Oga sighs, saying aloud that there's still one other person whom Hilda hasn't met yet.

Hilda is then brought to Aoi, who is quickly informed that Hilda has lost her memories. Hilda then introduces herself as being Oga's wife. Aoi, and everyone else, is clearly shocked by what Hilda said and how bluntly she said it. When Aoi proves her skepticism, Hilda restates her words and explains that she Oga is her husband. Furuichi and Nene take Hilda's words as a "declaration of war" to Aoi. Upset, Furuichi then runs away. He explains about the situation to Kazuya and Azusa Fujisaki who both proceed to Furuichi's former location. A lot of students have already gathered around the vicinity. They whisper about the apparent "lover quarrel" that Oga is having with Hilda, regarding Aoi. Hilda starts off by calling Aoi a "whore" and then asking Oga why he has another woman with him. Oga denies having another woman with him. Aoi then asks Oga why she's being badmouthed before sarcastically remarking on how good things are between him and Hilda. Oga denies anything between him and the Demon Maid. The situation tenses up. Hilda asks for Aoi's name but receives no full answer. Hilda then asks if Aoi has feelings for Oga causing her to blush in embarrassment, then run away with Nene chasing after her. Hilda then tells Oga that she's becoming scared, scared of remembering her true self.

Yolda's Return
Later during a lunch break, Aoi is fully told of Hilda's amnesia by the Red Tail. She becomes annoyed at Oga for not saying anything earlier. Oga and Furuichi eat their lunch on the rooftop with Hilda feeding Baby Beel, using a milk bottle. While eating, Furuichi recalls the events from the other day, after Akumano Academy had been burned down.

While playing more games at his house, Izabella explained how Hilda's memories were to be forgotten by the time she would wake up. Izabella explains further how Hilda killed her own emotions so that she could serve Baby Beel and that, maybe, if she were to awaken, she wouldn't be unhappy if her loyalty were to be replaced with love instead. Furuichi asks if the situation can apply to her and En's other wet nurses. Izabella confirms it but adds how there's three of them and one of Hilda. She then reveals that Hilda and Yolda are sisters, much to the surprise of both Furuichi and Lamia.

As the flashback ends, the two delinquents realize that Yolda has appeared and approached Hilda. Yolda berates Hilda for appearing so vulnerable and expresses her disbelief that she could have lost her memory. She begins to walk away but then pulls out a CD cassette, containing information on how to counter Salamander's memory-altering flames. She says how Salamander and the other Pillars are still in the Human World but still have yet to plan another attack. Yolda hands over the CD, saying that she's not going to want to think that she owes them anything in the future. Noticing Hilda's expression, she asks what's wrong. Hilda says that she doesn't want her memories to return and Yolda asks her sister if she's really forgotten about her duties as a wet nurse to Baby Beel. Suddenly, Hilda starts crying and runs away.

Prince Charming
In the school's computer room, Oga plays the CD on one of the computers. Baby Beel, as well as Furuichi and Yolda have accompanied him. As they're watching the video instruction in the CD, the group see several of the Pillars from Behemoth's 34 Pillar Division fishing for crayfish in the nearby river. The video continues and Salamander reveals that for Hilda to regain her memories, she needs a kiss from her prince charming, otherwise, she won't change. Oga angrily destroys the computer and scares Furuichi and Yolda, trying his best to pretend that they never saw the video.

Takumi Sadohara enters the room, causing Oga to run away as his teacher asks why the computer is broken. Furuchi and Yolda exit the room where they meet Aoi, who heard Oga destroy the computer. Yolda teases Aoi about her feelings for Oga and, using it to her advantage, says how Oga needs to kiss Hilda if her memories were to return. This shocks Aoi and she accidentally destroys part of the school. The other Ishiyama delinquents are then told the same thing and, feeling mischievous, chase Oga, trying to get him to kiss Hilda.

Oga manages to escape and hide behind some bushes. He encounters Lamia who gives him a small vial, a special medicine made by Furcas Rachmaninoff which is supposed to restore Hilda's memories. Oga is excited and he decides to go find Hilda, using Baby Beel as a tracker device. Furuichi, Aoi, and Yolda catch up to him and join him in finding Hilda.

Hilda is shown by the river back where the other leftover Demons from Behemoth's Division, albeit low-ranking ones, are fishing nearby. They notice and approach Hilda. Remembering her actions from before, they try to attack her but Oga steps in and defeats them before they can attack Hilda. Hilda thanks Oga for his actions and mentions how it must have been similar to when he first rescued her. She notices that he even has scars to prove it. Oga pulls out the medicine vial and Hilda, who realizes its properties, decides to use it. She says that she may have been happier before and that she doesn't mind losing her current happiness.

However, Baby Beel throws it in the river as he's happy with the new Hilda. Oga is annoyed but quickly gets over it, thinking that it might actually be a good thing. Hilda holds Baby Beel and silently kisses him while Oga continues talking; as he's doing so, he mentions how Hilda's cooking has improved since her memory loss. Hilda asks if it was bad before and Oga says how it used to taste horrible, almost as though she was attempting murder. Hilda snaps and angrily retorts that the next time, she won't be attempting such an action.

Oga and the others are clearly shocked and they realize that Hilda's prince charming was actually Baby Beel.