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Yggdrasil of the Summer Courses is the twenty-fifth novel of the High School DxD series. It is the fourth novel of the Red Dragon Emperor of the Blazing Truth × White Dragon Emperor of the Morning Star: The True Dragon(s) of the Kuoh Academy arc.


Let's show him! The heavenly dragon! Red dragon emperor!



  • Transcendental reason
  • Life.0
  • Life.1 A Female Teacher’s Formal Marriage Interview!
  • Life.2 The Ocean of Milk and the Maou’s [Game]
    • Balberith & Verrine
    • Vidar
    • Team member.1
  • Life.3 Battle in Yggdrasil
  • Life.DxD VS Life.GOD Challenge to the Gods —Red Dragon—
    • New Dark. From the Outside of the World's principles
    • Longinus
    • Qualifying Team
  • The First Rating Game World Tournament [Azazel Cup] Teams in the Main Draw
    • Gods of Hell
    • Team member.2
  • Next Life
  • Afterword


Main Characters Returning Characters New Characters Antagonists



“Even if you are a God, I will defeat you!” - Issei Hyoudou.

The battle of Hyoudou Issei who is a former human which began from the fight with the Fallen Angel――。

At last he rushes into a fight with God.

And, the arranged marriage between Rossweisse and the Nordic Chief God Vidar begins――。

High school D×D 25

Can you take me away from Vidar-sama?


You need to give an answer soon on what Rossweisse is to you. ―― Rias Gremory

It was the fiancee accustomed to being the legal wife who was thinking about Rossweisse.

If you think normally, our team is at an overwhelming disadvantage. ――Ravel Phoenix

The strength difference is too wide. ――But, our opponent has no openings.

You'll win without a doubt. ――Yuuto Kiba

That's right! I believe in Ise-senpai! ――Gasper Vladi

The Gremory boys believed in the victory of Issei.

Let me have my opponent, the sun god. Today I will be a little persistent. ――Xenovia Quarta

I see, you have the sheath of Excalibur? Well, let's have someone enjoy it. ――Olympus Chief God Apollon

I am the "Knight" of this team and Michael-san's Ace! I can't lose! ――Irina Shidou

You can't win in a decent fight. Then――.

Fafnir's panty lesson will begin. Ooooooooooo (tears)! ――Asia Argento

We got Asia's panties. I, am excited. ――Golden Dragon Fafnir

Yes, if you can't win in a decent battle, you have to hit someone not-decent!

There are those who want to train Hyoudou Issei. ――I would like you to join the ocean of milk (samudra manthana). ――Ajuka Beelzebub

Will it be an entrance to a new world?

If you're doing more lewd things, I'm glad to hear it!!――Rossweisse's grandmother・Gondul

The dialect was in full swing.

Issei nyannyan♪――Kuroka

Kuroka ane-sama! I, I also!――Shirone(Koneko)

After the proposal, the Nekomata sisters became bold.

Rossweisse, I think the time has come for you to answer. What Issei-kun is to you.――Akeno Himejima

For Issei, for Rossweisse――。

This is the new training field. However, you will need a cell phone.――Nakiri Ouryuu

The training ground prepared in place of the training space attacked by the Grim Reaper was a surprise from Ajuka Beelzebub.

Guhahahahaha! I will let you do as you like!――「Kings of the Game」『King』Typhon

The shortcomings of the opposing team are shown. However, it was too overwhelming too face.

HAHAHA!The tournament is a breeze, but now what kind of things will come out after this.――Indra

Finally qualifying has come to an end.

Just right. Tannin's son, be my practice partner.――Crom・Cruach

Nuguaaa! ......and, the legendary Evil Dragon is the practice partner......no matter how many bodies......。No, I will be the Sekiryuutei's Fang!――Bova・Tannin

I'm seeing terrifying things.

When you are by side of Hyoudou Issei-san, only things that are usually impossible occur......――Elmenhilde・Karnstein

Yes, it happens often......。

Please show me how much you have grown since that time. Rose.――Valkyrie Corps Captain Brunhild

……Senpai! I will not lose! I will surpass you!――Rossweisse

Rossweisse's opponent was――the strongest Valkyrie.

『The Miniature Garden of the Green Tree of Innovation』and 『The Ultimate Karma』......It is a terrifying combination, isn't it.――Roygun Belphegor

The Longinus that are still shrouded in mystery......its whereabouts――。


I wanted to fight you。

My kick、and your fist、which one will win!

――The Chief God of the Nordic Mythology Vidarr

The other party is a god!

But, you only have to do it!

To survive in this tournament、 also for Rossweisse-san!

I'll defeat you here!

Rossweisse-san is my friend, an important comrade, and――。

――Issei Hyoudou・Red Dragon Emperor

Preliminary round, the last battle!!

Open war!!


  • This is the final volume of High School DxD series. Next is the True High School DxD series.