Boosted Gear

The Boosted Gear, also known as the Red Dragon Emperor's Guantlet, is a Sacred Gear wielded by Issei Hyoudou. Listed as one of the 13 Longinus, it has the spirit of the Welsh Dragon, Ddraig, residing in it. It has the ability to double the power of the user in every 10 seconds.

Summary
In Volume 9 of the Light Novels, it is revealed that when a host of the Boosted Gear dies, their memories are zombified and stored inside the Gear. However, there are two people who did not become zombies; Belzard and Elsha. Belzard is known as the strongest Boosted Gear possesser for defeating 2 White Dragon Emperors in his lifetime, while Elsha the second strongest and the strongest female. In Volume 12, all the past possessors sacrifice themselves to save Issei's soul.

Appearance
In its initial state, the Boosted Gear looks like a regular Twice Critical. After a certain time, it transforms to a more Dragon-like gauntlet that covers up more of the user's hand. When the Boosted Gear reaches its second liberation, it gains another green jewel and once again covers up more of the user's hand.

Abilities
The Boosted Gear has the ability to double the power of the user every ten seconds. With futher change in response to the user's feelings, the Boosted Gear can transform into the Boosted Gear Gift, which has the abilty to transfer the increased powers to other people or objects.

Its Balance Breaker, the Boosted Gear Scale Mail, creates an armor that covers the user's body and grants futher power to the user. When active, the user can double their power at will.

The Boosted Gear also has a forbidden form called the Juggernaut Drive. The Juggernaut Drive releashes the full power of the Welsh Dragon, but the user will lose their sanity and their life will be devoured. However by the beginning of Volume 12, the curse of Juggernaut Drive has ended.

Weaknesses
With Ddraig sealed within the Boosted Gear, its possessors become vulnerable to Dragon-slaying magics, swords, and curses, as if they themselves were Dragons. Also, continuous use of the Boosted Gear will drain the wielder's stamina to a significant degree.

Announcements

 * Dragon Booster: Summons the Boosted Gear.
 * Boost: Doubles the user's power. This call is announced every 10 seconds until the user reaches his/her physical limit. In Balance Breaker mode, this call is announced repeatedly until the user reaches his/her limit.
 * Explosion: Releases the Boosted Gear's stored power for a short period of time.
 * Reset: This announcment is called after all the Boosted Gear's stored power during Explosion is drained. Once called, Issei can use Boost again until he releases another Expolsion, so long as his body is not near his physical limits.
 * Burst: This announcement is called when the Boosted Gear's wielder reaches his/her physical limit. Once called, all of the user's increased powers are drained.
 * Dragon Booster Second Liberation: Changes the Boosted Gear into the Boosted Gear Gift. This announcement was only used once in the Rating Game between Rias and Riser.
 * Transfer: Transfers increased powers to other people or objects.
 * Welsh Dragon Over Booster/Welsh Dragon Balance Breaker: Activates the Scale Mail armor, Boosted Gear Scale Mail. The first call was used in Issei's final showdown with Riser, while the second (and subsequent) call was used during Issei's battle with Kuroka.
 * Vanishing Dragon Power is Taken: This call was announced when Issei formed the Dividing Gear with one of Albion's jewels during his battle with Vali.
 * Sword: Summons Ascalon.
 * Juggernaut Drive: Activates Juggernaut Drive.
 * Longinus Smasher: The chest armor of the Scale Mail slides open and fire a powerful shot. In Volume 12, Ddraig reveals this is a forbidden and sealed attack.
 * Jet: Allows Issei to fly through his Dragon Wings while in Scale Mail mode.
 * Change Star Sonic: Used in Illegal Move Trident. Changes the Scale Mail armor into the Welsh Sonic Boost Knight.
 * Change Solid Impact: Used in Illegal Move Trident. Changes the Scale Mail into the Welsh Dragonic Rook.
 * Change Fang Blast: Used in Illegal Move Trident. Changes the Scale Mail into Welsh Blaster Bishop.
 * Cardinal Crimson Full Drive: Activates Cardinal Crimson Promotion.
 * Bust: Announced whenever Issei touches Rias' breasts. This replenishes Issei's power and stamina, albeit at the cost of Rias' breasts shrinking with each use (though they do grow back to normal within a day's rest, according to Rias). This announcement is called repeatedly.
 * Star Sonic Booster: Used while in Cardinal Crimson Promotion. Grants the user god-like speed that far surpasses Welsh Sonic Boost Knight's.
 * Solid Impact Booster: Used while in Cardinal Crimson Promotion. Morphs one of Cardinal Crimson Promotion's fists into one of the Welsh Dragonic Rook's, allowing for an enhanced version of Solid Impact.
 * Fang Blast Booster: Used while in Cardinal Crimson Promotion. Fires the Crimson Blaster, an enhanced version of Welsh Blaster Bishop's "Dragon Blaster".

First Form: Twice Critical
The initial form of the Boosted Gear. It takes a form of a red, armored bracer with yellow accents and a green jewel on top of the palm area. The fingers aren't covered. Initially, it was mistaken as a Twice Critical.

Second Form: Boosted Gear
A form where it was finally realized that it is a Boosted Gear. It first debuted during Issei's last battle with Raynare. It is a red, claw-shaped guantlet with yellow accents and green insctiptions. It is also known as the Dragon Booster.

Third Form: Boosted Gear Gift
Boosted Gear Gift (赤龍帝からの贈り物(ブーステッド・ギア・ギフト) Būsuteddo Gia Gifuto), also knonw as the Gift from the Red Dragon Emperor, is Boosted Gear's third and final form in the shape of a gauntlet. It has the same appearance as the original Boosted Gear, albeit with a second jewel that grants the user the Transfer ability and that it covers more of the user's hand. It debuted during Rias' Rating Game against Riser.

Dividing Gear
Dividing Gear (白龍皇の籠手（ディバイディング・ギア） Dibaidingu Gia), also known as the White Dragon Emperor's Gauntlet, is the Boosted Gear version of Divine Dividing. It debuted in Volume 4 during Issei's fight against Vali, where the former placed one of Albion's jewels on his right gauntlet. With the Dividing Gear, Issei gains all the powers of Divine Dividing. However due to it consuming his lifespan, it was banned from use by Azazel.

Scale Mail
The Balance Breaker of Boosted Gear which creates a Red Dragon Armor with green Jewels that covers the users body and strengthens its powers and abilties.

Normal Balance Breaker
The initial state for Boosted Gear's Balance Breaker. It initially did not have a wing, but after Issei gets into Juggernaut Drive in volume 6, it gains a Dragon wing.

Illegal Move Trident
Illegal Move Trident is the enhanced form of Issei's Scale Mail, where the armor changes to various forms based on the Evil Pieces' traits.

Cardinal Crimson Promotion
Cardinal Crimson Promotion (真紅の赫龍帝（カーディナル・クリムゾン・プロモーション）Kādinaru Kurimuzon Puromōshon), also known as the True Crimson Dragon Emperor, is Scale Mail's Queen form that debuted in Volume 10 of the light novels during Rias' Rating Game battle against Sairaorg. It changes the color of Issei's Scale Mail armor from red to crimson. Cardinal Crimson Promotion incorporates all three Evil Pieces traits, making it the most balanced and most powerful form of Issei's Scale Mail. It is Issei's answer to a power different from the Juggernaut Drive, making it equally as powerful as the latter. This form, however, is still unstable and requires mastering the three forms of the Trident to stabilize its powers.

When Issei first used Cardinal Crimson Promotion, he uses a modified version of the chant for Juggernaut Drive.


 * "I, who is about to awaken
 * Am the Red Dragon Emperor who has discarded the principles of domination
 * I shall walk the road of righteousness by having infinite hopes and dreams
 * I shall become the King of Crimson Dragon
 * And I promise you all! I shall show you the future which shines in true crimson light!"

Issei uses a slightly different chant in Volume 11 during his battle with Shalba Beelzebub.


 * "I, who is about to awaken
 * Am the Red Dragon Emperor who holds the truth of the king up high
 * Holding the infinite hopes and unbreakable dreams and walking the path of righteousness
 * I will become an Emperor of Crimson Dragon
 * And I will lead you to the Path of Heaven, glowing in deep crimson light!"

After which the Boosted Gear announces "Cardinal Crimson Full Drive!"

Juggernaut Drive
Issei went into Juggernaut Drive in Volume 6, which was also his last time. In Juggernaut Drive, Issei's Scale Mail assumes the form of a mini-Ddraig, and has access to the form-exclusive Longinus Smasher.

Super Gigantic Balance Breaker
The form Issei takes after combining with Great Red in Volume 12. It looks the same as Boosted Gear's normal Scale Mail, except it is very enormous and has access to the Longinus Smasher that was previously exclusive to the Juggernaut Drive.

Trivia

 * Cardinal Crimson Promotion is modeled after the ZGMF-X10A Freedom Gundam from Mobile Suit Gundam SEED.