It was seven years ago when Vali was taken in by Azazel.
Vali had been abused by his dad and Rizevim.
Vali didn't retaliate the abuse because if he did his dad would have abused his mother instead.
Vali's dad thought he was special because he was a "Lucifer". But Vali was even more "special". Hence the abuse to make himself feel better.
The one who told about Vali to Shemhaza to help him was the servant of Vali's dad.
He was most likely killed in doing so.
Vali was stronger than most SG users after a year passed since he was taken in.
He vowed to be stronger than original Lucifer, Rizevim, and Great Red.
He was also looking forward to his future rival: Sekiryuutei.
5 days passed since Trihexa revived.
The top brass of different factions are sitting to watch the horror of Trihexa and discuss the counter measure.
It destroyed the main institute belonging to Grigori and the Heaven (from First Heaven to Sixth Heaven).
Many Angels died in a process (Even ones who had been fighting since long time ago).
Three Seraphs were critically wounded. Most of the Four Great Seraphs were also wounded.
Rafael lost one of his leg. Uriel lost an eye and arm. Even Michael was wounded.
Even two of the leaders of the fallen angel was wounded badly.
The situation was even worse because of the fake Sekiryuuteis and Evil Dragons. The ones leading them were Apohis and Aji Dahaka.
On the third day of its release it went to Norse world.
Many Gods and ultimate class Devils were dispatched to fight the enemies. Gods mainly from Asura Gods.
On the fifth day Trihexa and co, teleported elsewhere so it couldnt completly destroy Norse world.
Sirzechs who wasn't present in the discussion arrives and reveals the info about Rizevim and Trihexa to the public.
Then that vampire girl (Elmehilde or whatver she was called) arrives and passes on a info about the secret of Holy Grail which Rizevim didnt know about to Azazel.
Sirzechs and Azazel talks about a certain things like a certain Rating Match they hoped to see but possibly cant now because of a certain thing they must do (death flag?)
And the so-called other world is a place where the species known as E×E (mechanical organism) and the spirits are at war with each other (according to Azi Dahaka). And both sides have a certain God that rules them. Maybe ExE is above Great Red then?
Spoiler for Ophis & Lilith: They both survive and didn't merge. Good for everyone.
There are casualties (but no one from the regular cast dies). Leaders of many factions seals themselves with Trihexa to stop the world from being destroyed. So pretty much...
Sirzechs and his peerage (minus Grayfia)
Serafall and her peerage (minus her Queen)
Falbium and his peerage (minus his Queen)
Michael and his brave saints (minus Irina)
Rafeal and his brave sainst (minus his Ace)
Uriel and his brave Saints (minus his Ace)
From the Norse faction it was Odin and 6 other Gods
From the Greek faction it was Zeus and 10 other Gods
From the Hindu faction it was Brahma, Vishnu and 7 other Gods.
As usual thank n0m@n for the spoilers.
High school D×D 21
To protect someone, huh.. It wouldn’t sound like me but I’m thinking that isn’t so bad. ――Hakuryuukou Vali Lucifer
I don’t want you to push yourself…but I’m sure you will end up fighting. ――Rias Gremory
The man she loves chose to stand even if his heart and body was shattered.
I will also continue to fight while believing the safety of Ise-kun ――Himejima Akeno
She had clearly became stronger compared to back then
A war is something new to me but I guess I would need to fight ――Kiba Yuuto
The clash against the Trihexa and the Evil Dragons would turn into a huge war which will drag every forces into it.
…Even someone with a God-class power can’t beat it… ――Toujou Koneko
Trihexa’s power great surpassed that of one’s imagination where it’s strength easily surpassed that of Gods.
I-I have prepared the Phoenix’s Tear… ――Ravel Phenex
A magnificent item that was made by Ravel.
Irina, Asia, this is the decisive battle! Let’s go! ――Xenovia Yes! For the Heaven! For the people! And for everyone’s sake! ――Irina Yes! I will protect everyone! I will make sure to protect them to the end! ――Asia
The two Holy-sword wielder and the Holy Girl who would protect everything descends down to the battlefield.
There’s someone who you want to settle the score with, isn’t there? Then leave this place to me! ――Bikou Our leader is Vali-nya! ――Kuroka Aren’t you going to show us more entertaining situation to me and the Holy-King sword? ――Arthur Pendragon I! I like the both of the Heavenly Dragons of this era! ――Le Fay Pendragon
The troublemaking comrades of the White Dragon agrees to White Dragon’s determination
We shall stop the Emperor of the Beast with the spell that we created!――Rossweisse
Her research would become one of the key in this decisive battle
Now then. I shall make my move as a part of DxD――Sun Wukong Ah man, I was supposed to be retired… But I’ll be in trouble if I don’t fight!――Jade Dragon Mother and I shall also fight! ――Kunou Hohoho, this is the part we have to give our all. ――Yasaka A mere herds of Evil Dragons will be slaughtered by my servants and I! ――Tannin
Dependable allies gathers from the parts of the world under the world’s danger.
Rizevim, you sure have died while leaving behind such troublesome thing…but don’t think everything will accordingly as you planned. Do not underestimate me――Azazel
The elder of the Fallen Angels makes a strong decision to what the son of the former Lucifer had behind.
…He’s my pal… Are you going to insult Hyoudou Issei!? I won’t allow that! `――Saji
He couldn’t forgive the words that insulted his peer who had fought of the Underworld and his comrades――
So the opponent is going to be the Trihexa… Interesting! ――Crom Cruach
The Evil Dragon male didn’t take a step back even against that ‘monster’.
Then I shall also fulfill my duty as a Maou then. ――Sirzechs Lucifer
The current Lucifer makes his move!
And the Longinuses which can even slay Gods gather――
Longinus. Canis Lykaon――Balance break ――Jin, we shall slash everything. We were given the order that we can go all out today ―― Slash Dog
Longinus. Zenith Tempest――Balance break I shall make you taste what a trump card means! ――Joker Dulio
Longinus. Absolute Demise――Balance break Va-kun, you absolutely cannot become reckless on your own, okay? ――The Magician, Lavinia the Ice Princess
Longinus. Regulus Nemea――Balance break Even if it may destroy my body, come into my fist! The shine of my life! ――Sairaorg Bael
Longinus. Sephiroth Graal――Balance break Ufufu, I’m happy if someone like me can become a help. ――Valerie Tepes
Longinus? Forbidden Invaded Balor――The beast I will definitely retrieve Valerie’s Holy Grail! And I will definitely let no one lay a finger on her! ―Gasper Balor
Longinus. True Longinus――Balance break Now then, the will possessed in the spear. What will you tell me in this situation? ――Cao Cao
Longinus. Divine Dividing――Balance break Azi Dahaka, I shall settle my score with you!! ――Vali Lucifer
Longinus. Boosted Gear――Balance break Apophis! Trihexa! I won’t let you guys do as you want! I won’t allow any more destruction even if that means that my body will reach its limit! ――Hyoudou Issei
The destruction which will devour all――
In order to stop it, the DxD, the Longinuses, the warriors of different forces that had overcome their differences gathers――
Bring it on, Hakuryuukou! Show me what a real Lucifer is made of! ――Azi Dahaka
I heard you have opened the door that surpasses the Crimson armour. Sekiryuutei, you cannot defeat me unless you use it. ――Apophis
The two Evil Dragons that are more powerful than Rizevim Livan Lucifer stands in front of the two Heavenly Dragons!
The Hakuryuukou who was satisfied as long as there was battles――
The Sekiryuutei who simply wanted a daily life where he can simply live with laughters――
But the answers these two reached after this battles was the complete opposite――
It was a battle which was enough to change Hyoudou Issei’s thinking ways and life.
Volume 21 will be on Vali, but other characters will also shine. Ise will also play a major role. What will Ise and Vali choose at the end. Fans please wait a little longer. More like, the content of this volume will be more darker than usual, be prepared for it.
Also from Ishibumi's blog. Because he placed more effort on Volume 21, it'll be thicker than usual. (Too bad Miyama might not do the same with the illustration though.)