The Diabolos Dragon form is first seen in Volume 20 when Issei received the full support of his parents, unlocking it with Ophis' help. With it, he was able to overcome Rizevim's Sacred Gear Canceller and quickly defeat him. However, the immense power of the form caused him to painfully collapse after its release.
Vali also attains his own version of the Diabolos Dragon in Volume 21 with Ophis' assistance. However, Vali's version is powered by syncing his previously dormant power of Lucifer with Albion's own. In the same Volume, after Issei's battle against Apophis and the Trihexa Core, Ophis reduces the power of Issei's Diabolos Dragon and removes the "infinity" aspect in it, successfully eliminating the life-threatening setbacks it previously had.
Diabolos Dragon God
Diabolos Dragon・G (龍神化－『D×D』・G－) is Issei's version of the Diabolos Dragon. The armor becomes colored in a mix of crimson and black and a second pair of Dragon wings appear on its back, totaling in four. After the battles against Apophis and Trihexa, Ophis reduces the power of the DxD G and removes the infinity in it to remove its almost fatal side-effects. This adjusted DxD is dubbed Pseudo-Dragon Deification. The form can only be maintained for a maximum of three minutes at a time, but attacking, defending and moving will further reduce this time limit, to the point that usage in actual combat generally amounts to nothing more than ten seconds. After drinking the effects of Amrita, his countdown of his Pseudo-DxD changed from ten seconds to eighty-eight minutes, reflected by  on his left gauntlet.
- Infinity Blaster: A further enhanced version of the Crimson Blaster. Similarly to Cardinal Crimson Promotion, DxD's wings contain hidden cannons. These four cannons shoot out a powerful blast of red and black aura that can injure even a Super Devil like Rizevim to the point of near-death. A single usage of the blast in Pseudo-DxD will reduce the time limit of three minutes to ten seconds.
- Longinus Smasher: This form is not only capable of this move, but the blast it shoots out has been enhanced with the power of infinity. When used in tandem with the Infinity Blaster, the two attacks can merge into an even more powerful blast capable of penetrating through the attacks of the Evil Dragon Apophis, who had reached Heavenly Dragon-class in power and damaging him fatally.
- Dress Break DxD, an enhanced version of the spell augmented by the Diabolos Dragon armor, by using his Dragon God aura, he can halt his target’s movement. While strengthening his left hand he can destroy a female uniform without touching it.
- Ddraig Manifestation: Due to drinking the miracle drug Amrita, Issei gained the ability to summon Ddraig into battle after the  countdown on the right gauntlet reaches zero.
Diabolos Dragon Lucifer
Diabolos Dragon・L (魔王化－『D×D』・L－) is Vali's version of the Diabolos Dragon, which is achieved through the combination of the powers of Albion and Lucifer dubbed Maouification by Aži Dahāka. The armor becomes colored in a mix of silver and black and gains twelve mechanical Devil wings. This form can only be sustained for a short time that has yet to be revealed in detail.
- Satan Compression Divider: Vali releases a burst of silvery-white and jet-black light that instantly compresses anything caught in it to the point of non-existence.
- Satan Lucifer Smasher: An enhanced version of the Boosted Gear's Longinus Smasher. Much like with the former, the armor plates on the chest and abdomen slide open to reveal a cannon muzzle that promptly fires a massive bombardment of silver-white and jet-black aura. When hit directly, this attack is powerful enough to fatally injure Aži Dahāka, an Evil Dragon who had reached Heavenly Dragon-class in power.
- Dividing Wyvern Fairies: In this form, Vali can detach his wings and shape them into small white Wyverns that can use Divide, Reflect and Half Dimension. The Wyverns are also able to morph into cannons that fire out powerful shots of Lucifer’s aura. The Wyverns are also able to use Albion's Reduce ability, a deadly poison that can destroy even Gods by cutting down not only their bodies, but also their souls. However, this poison is ineffective towards Ophis, Great Red and Ddraig.
- Issei: The Crimson Red Dragon dwelling within me, awaken from your dominance
- Ophis: The Crimson Heavenly Dragon I possess within me, rise up to become a King and roar
- Ophis: The jet-black God of Infinity
- Issei: The glorious God of Dreams
- Both: Watch over the (false) forbidden existence we shall become that transcends the boundaries
- Both: Thou shall dance like radiance within our inferno!
- Vali: The pure White Dragon dwelling within me, rise up from your supremacy
- Albion: The silvery-white Morning Star I possess within me, claim the throne of Dawn
- Ophis: The jet-black God of Infinity
- Vali: The mysterious and unfathomable father of Devils
- Vali and Albion: We shall transcend the limits to accept the oath
- All: Thou shalt kneel down before our bright and glorious existence!