Flower Arrangement of the Princesses:
Rias, Sona, and Seekvaria are having a chat in an underworld cafe with their knights as bodyguards. Seekvaria’s Knight is Bafeel Fercas who is the younger sister of Sairaorg’s Knight Beruka Furcas. The topic was just teenage girls stuff and post war treatment, but changes to about bridal training. Rias remembers how Issei's mom talked about her training, so Rias wants to learn as well to be a proper wife, as she wants to be an educated Japanese wife with proper Japanese knowledge such as flower and tea ceremony, because she’s marrying a Japanese man, she wants to have enough knowledge so she doesn’t shame this land. Seekvaria misunderstands flower arrangement as for robots due to pronunciation issues. Sona ask Rias why not ask Akeno for lessons, but she says that Akeno doesn’t have any style as she just imitates or she herself is trying to find someplace to learn. Sona decides to take her to one and join her as they're friends, and Seekvaria decides to join as she spends too much to in her lab, so experience other cultures could be fun.

They invited all the girls from their peerage to join them, but they decline as this should be something for the kings to experience, but their knights will join them to act as bodyguards. Issei wasn’t told as this is for him and she’s training to be his future wife, as he is their future husband Kiba was embarrassed as he was the only guy there, decided to use the gender swapping ray on himself to join them even though he never planned on using it again as he must fulfill his duties as a knight. Everyone is wearing kimonos, including Kiba who is wearing one for the first time, so he’s unfamiliar in it. Tomoe took a picture of Yumi in a kimono on her smartphone. They arrived at a school that is willing to teach flower arrangement to even devils, knowing that they allowed devils gives Kiba a bad feeling. The door opens and a middle aged woman Bakusan Umeko wearing a kimono and a head vase and she releases an aura which Kiba says it’s a dense aura that a teacher shouldn’t give and he no longer sees this a teacher for a flower classroom. Their test is to release their aura, so she can evaluate it. They must show their auras as it’s needed to learn here. They do it, and their aura destroys the entrance and their surroundings. They pass the first test.

Inside the school appears to be a spacious wooden dojo room, where all the woman wearing kimonos are using flowers as swords and vases. Kiba sees lots of people doing fighting poses. The teacher says that every day the students train as if preparing for combat and flowers are the most important aspect of their training. The teacher allows the students to use props to help encourage their imaginations, which Kiba questions in his mind what is the actual meaning. Umeko asked if they know the origin of flower arrangement and Sona gives an in depth explanation. Kiba thinks to himself that he expected a normal Japanese class, where people simply sit and perform flower arrangement, what he’s seeing makes him think they're in a warrior and ninja school. Rias thinks this is all part of flower arrangement and Kiba is worried on how gullible Rias is with Japanese stuff and how she became like this. Umeko says that the old way of flower arrangement is dead and this school discovered a new way of training. Umeko gives a Japanese Linguistic lesson on how scent, handsome, and flowers are similar to each other. Rias thought this was a wonderful atmosphere, and Seek have prepared an army of prototype robots. Kiba thinks this is going to give bad memories.

Rias meets another student who is describe to be arrogant. Both Rias and she enter a stage where they will practice flower arrangement. Both are given flower-shaped swords and are given an explanation about the sword's origins. On a table there are flowers, fruits, and vegetables. And with those swords they must prepare them. Rias gets the first move and decides to use the sword to pierce a bamboo shoot. She gets 40 points. Kiba is shocked as the sight of piercing a bamboo shoot with a flower sword felt surreal and that there is a point system. The student then started sweating and used the sword to pierce a watermelon which caused to bloom like a flower and split into 8 equal pieces gaining 40 points too. Kiba is confused as they're using bamboo and watermelons to arrange flowers, and said that if Issei were here, he'd question all this aloud, and Kiba misses that Issei isn’t here to question all of this. Kiba sees Seekvaria has put one of her robots on the tip of her flower sword. Sona thinks she made a mistake bring them here. Kiba and the other knights dont know how to properly respond to this situation. During Rias' battle, apparently that bamboo shoot from the very beginning has grown thanks to the spiritual power of the sword plus bathing in her own aura has grown to become a miracle which causes Rias wins. The student mentions that who she fought was the weakest one of the 4 Heavenly Kings, the other 3 will now challenge her, which she accepts. Sona smiles seeing how happy Rias is and admits to being a little jealous on how so much in love she is. Kiba and the other knights decide to join her in this unconventional flower classroom.

Kiba is at Issei's house and sees the bamboo shoots that Rias pierced. Rias is happy of her work and has done the flower arrangement to the entrance of the house. Rias decides to challenge all the other schools. Kiba as her knight has to accompany her, Kiba remembers all that they were taught and questions as a man when will he ever used them.

When you turn into a Devil, one of the unique ability you attain is “Language”. The moment you turn into a Devil, everyone in the world can understand what you are saying. People listening to you will hear it in the language they are most familiar with. If they are American, then they will hear it in English. If they are Spanish, then they will hear it in Spanish. And also the opposite. If they speak in a language besides Japanese, you will hear it in Japanese.”

Yeah, its happening just like Buchou said.

During the English lecture, I heard everything in Japanese. I was shocked. When I was told to read an English paragraph by the English teacher, I somehow read it and all of my classmates looked shocked.

Of course they would. Since I can speak English naturally now, so obviously my classmates will be shocked.

Even the teacher froze because of it.

Well, the letters and vocabulary didn’t change to Japanese because it’s limited to sound only.

But that’s good enough. It’s too amazing if I can exchange language anywhere in the world.

Just like that, I turned into an “international” high school student without any requirements.

Unknown Dictator name is Magnus Ross (マグナス·ローズ ) He's a White Male CIA agent

In UK, Arthur meets with the Current Head of the Pendragon Family and Elaine is at the sidelines. Alphecca Tyrant is related to the British Royal family. The British Royal Family have hid its info so Heaven and Grigori are having difficulties finding it. The Head told Arthur if he can handle Alphecca Tyrant, he'll recognize their relationship, which causes both Arthur and Elaine to blush. The Head asked Le Fay if she's in love with Issei. Arthur thinks about the Welsh Dragon origin in myth and their connection with their family. Arthur then wonders if Le Fay will become a Devil, while their parents are still human, and because of their values are different than their father. Arthur wonders how will the future will develop.

At the end of the Preliminaries, Vali has recruited Salamander Tomita and the Ninja Master from DX.2 to his team.

Everyone is looking at pictures of Rias' bridal training during Flower Arrangement and sees Yumi in those pictures. The girls believe Yumi in a kimono is a strong enemy.

After Vali learned that Lavina has his old books, he constantly sent assassins to attack her. It ended when Lavina froze Vali

Issei and Rias have been eating at several restaurants. They arrive at another restaurant where they see Cao Cao, Vali, and 16-17 year old Genbu. There's a subtle atmosphere between Vali and Genbu. Benbu's blushing while Vali said it was just a chanced encounter.

Issei on the roof drinking cola and thinking about the Longinus. His mom and the Loli 3 came to the roof to dry the washed clothes. Issei saw a pair of black panties and thought of the First Errand SS.

Issei got Ophis' clothes back from drying and sees the 3 Lolis (Ophis, Lilith, Kunou). And feels at peace looking at them. His mom says to get his clothes too and she'll help. Issei is happy with this daily peaceful life.

Resurrected: Between 17-19 (No definitive timeframe in when)
Unknown Dictator: During Azazel Cup Qualifier
Maid of Pendragon: Between 17-19 (No definitive timeframe in when)
Collbrand: Post Azazel Cup Qualifier
Sleepover of a Gifted Person: Between 17-19 (No definitive timeframe in when)
Salamander Tomita: Post Azazel Cup Qualifier
Dark History: Some time after V24 where the books were introduced
Restaurant: Post Azazel Cup Qualifier
Super Hero Trial: Between 24-25 (No definitive timeframe in when)
Infinity Underwear 1: Current Time
Infinity First Errand: Post V12
Infinity Underwear 2: Current Time
Because Ishibumi was sick, Dx5 was released instead of Shin 3 and SD 4. As of now, he's working on them, and hopes fans enjoy 2nd Kyoto trip and the Kunou(Yasaka) volume.

The idea of Le Fay possibly becoming part of Issei's peerage was finally put forward in story