Vritra's Cursed Gears

Vritra's Cursed Gears, also known as the Abyssal Prison Dragon's Machines, are several Ancient Gears that contain the spirit of Vritra, the Black Dragon King also known as the Abyssal Prison Dragon. Seven of these Ancient Gears are currently held by Lancelot Du Lac of the Hero Clan.

Summary
In Volume 3, Lancelot reveals that he owns two of Vritra's Ancient Gears, Absorption Line and Inferno Black Flare, which both contains parts of Vritra's soul in it.

In Volume 6, Lancelot reveals that a jewel appeared in his hand and gained many black snake-like marks after absorbing Percevall's blood and some of Seiryuumaru's power during their battle with him and Kaoru Nonaka.

In Volume 7, Lancelot's abilities were upgraded when Grigori, on the order of Azazel, implanted the five other Vritra Ancient Gears into Lancelot, thus completely awakening a part of Vritra's consciousness. This gives Lancelot the new ability, "Vritra Coronation".

Lancelot was able to reach Overdrive, Malebolge Vritra Promotion in Volume 17. His Overdrive is the result of the combination of the seven Vritra Ancient Gears and the fusion of Lancelot and Vritra.

In True Volume 2, thanks to Ophis' and Wagyl's blessing, Lancelot now has the ability to access Diabolos Dragon Beast with Vritra and Wagyl, dubbed Diabolos Dragon Beast: Vritra.

Absorption Line
Absorption Line, also known as the Evil Prison Dragon's Pulse, is one of the two Ancient Gears residing in Lancelot. It resembles a small lizard (more specifically, a chameleon) with a deformed face that appears on the user's hand. Lancelot is also able to form Absorption Line on both his arms and legs. It has the ability to make lines of connections that allow the user to either absorb or transfer power from opponents, allies, and objects.

Inferno Black Flare
Inferno Black Flare, also known as the Evil Dragon's Domain of Flames, is one of Vritra's Ancient Gears that grants Lancelot the ability to unleash Vritra's deadly black flames to burn his opponents.

Kin Vala
Kin Vala, also known as the Younglings of the Evil Prison Dragon, is one of Vritra's Ancient Gears. It has the ability to summon several small, Vritra-like Dragons that follow Lancelot's commands, and can be equipped with weapons by holding them in their mouths. Lancelot can also equip a cloak like the one worn by his Dragon Knights in order to protect his body or trick his opponents by hiding in the army.
 * Valall Shrouded Army, also known as the Black Demon Children of the Evil Dragon, is Lancelot's Overdrive of Kin Vala.

Sleeping Camo
Sleeping Camo, also known as Prison Dragon's Skin, is one of Vritra's Ancient Gears that grants Lancelot the ability to conceal the presence of other people and his own, similar to camouflage.

Delete Field
Delete Field, also known as the Domain of Abyss, is one of Vritra's Ancient Gears. It has the ability to suppress the opponent's powers.

Abyss Prison
Abyss Prison, also known as the Prison of the Black Dragon, is one of Vritra's Ancient Gears that allows Lancelot to use Vritra's shadowy aura to restrain his opponents.

Snake Web
Snake Web, also known as the Shadow Cell of the Evil Dragon, is one of Vritra's Ancient Gears that grants Lancelot the ability to create poisonous spider webs that can trap and poison opponents, similar to Abyss Prison.

Vritra Coronation
Vritra Coronation, also known as the Prison Dragon King Transformation, allows Lancelot to take the form of a black dragon and use black flames. The flames can also restrain the movements of enemies, as well as absorb their power. This form allows Lancelot to use all of Vritra's abilities in unison. However, it has been known to put Lancelot in a frenzied state, being driven on pure instinct and barely able to form coherent dialogue.

Malebolge Vritra Promotion
Malebolge Vritra Promotion, also known as the Dragon King's Flame Prison of Guilt, is Lancelot's irregular Overdrive which creates a Jet-Black Dragon Armor that strengthens the users powers and abilities. This form was achieved when Lancelot and Vritra fused, and Lancelot had undergone true-dragonification. The armor has tentacles that absorbs an opponents aura until it turns them into ashes. The jet-black cursed flames are also strengthened to the point where they are able to counter the holy flames of Incinerate Anthem. The user can now inflict multiple curses onto other beings, it's noted that it will curse anyone to death if approached carelessly.

Diabolos Dragon Beast: Vritra
  Is the new form that Lancelot obtains in True Volume 2. It is very similar to Arthur's Diabolos Dragon Beast: Lilith and Vali's Diabolos Dragon Beast: Phoebus forms in the fact that the armor is organic and it is a mixture of purple, silver, white and black the difference is it has 10 mechanical Dragon wings and several tentacles, similar to Vritra Coronation. Its finishing move is the Vritra Inferno Cannon.

Lancelor, Vritra, and Wagyl alternate lines when chanting the Diabolos Dragon Beast: Vritra chant.
 * Lancelot: "The Abyssal Dragon King and dwelling within me, awaken from your prison of sins"
 * Vritra: "The Prison Dragon King I possess within me, revamp your crown and claim the throne of the Dusk"
 * Wagyl: "The rainbow God of the Dreamtime"
 * Lancelot: "The essence of the knight of lake and his kindred"
 * Vritra and Wagyl: "Watch over our forbidden existences that eliminates the boundaries"
 * All: "Thou shall scream in prayer under our sacred existence!"

Trivia

 * Malebolge Vritra Promotion is a reference to Malebolge, the eighth circle of hell in Dante's Inferno. It is considered to be the worst punishment reserved for sinners and those who try to escape it are shredded to pieces by the demons that inhabit the level.
 * Malebolge Vritra Coronation means "Evil Ditches of the Enveloper Coronation" since malebolge means "evil ditches" and Vritra means "the enveloper".
 * Vritra Coronation then just means "The Enveloper Coronation".