When Vali appeared in Volume 3, he was already in his Balance Breaker form, a perfect version of the Scale Mail.
Issei achieved his perfected version of the Scale Mail in Volume 5 after poking Rias' breast. After gaining the Scale Mail, it soon became the primary battle form for both Issei and Vali.
The Scale Mail generates a Dragon Armor while drastically increasing the user's power, abilities, speed, and defense. It also temporarily allows the user to use the power of the Boosted Gear and Divine Dividing without the 10-second interval. The armor is also capable of repairing itself from almost any damage it takes.
Wearing the armor and the duration it stays activated depends on the users physical and mental condition, otherwise it can be severely lethal to them, so the Sacred Gear forcefully removes the armor when the wearer reaches their limit as a fail-safe.
How much the armor repairs itself depends on the wearer's stamina.
Even with the protection of the Scale Mail, the wielders are still susceptible to Dragon-slaying attacks.
When Issei first attained his Balance Breaker, it had the following weaknesses:
- Activating Scale Mail takes approximately two minutes, during which a countdown begins on the gauntlet gem. During this period, he cannot cancel the process, or use other abilities such as "Boost" or "Transfer".
- Initially, it could only be used for half an hour once a day, and his Sacred Gear becomes powerless for the rest of the day. Also, in Scale Mail mode, each use of the "Boost" and "Gift" ability reduces the remaining amount of time of his Balance Breaker.
As of Volume 14, Issei has already overcome these weaknesses.
Boosted Gear Scale MailEdit
The Scale Mail of Boosted Gear used by Issei creates a Red Dragon Armor with green jewels that covers the body of the user. This armor has a pair of rocket thrusters at the back that gives a temporary boost of speed and flight, assisted by the retractable Dragon wings that comes out of it. In this form, Issei can double his power any time he wishes, but at the cost of a large amount of stamina and magical power.
In Volume 8 of the light novels, Ajuka Beelzebub, one of the Four Great Satans and creator of the Evil Pieces system, remodels Issei's Pawn Evil Pieces so that he can use Promotion anytime and anywhere he wants. During Promotion, Issei can now use Illegal Move Triaina (赤龍帝の三叉成駒, Irīgaru Mūbu Toriaina) to change his Scale Mail armor into other forms.
In the last episode of season 3, Ajuka makes a similar modification to Issei's Evil Piece which allow Issei's Balance Breaker to change in conjunction with his Pawn promotion. At the end of the episode, Ddraig tells him that a new path has been opened. Whether this is actually the Illegal Move Triaina has not been stated.
Cardinal Crimson Promotion (真紅の赫龍帝, 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 armor 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. However, for full use, it requires all Illegal Move Triaina forms to be fully developed and mastered before it can be completely stabilized, and its full power brought out.
It is stated to be Issei's answer to an alternative for the Juggernaut Drive.
To enter into Cardinal Crimson Promotion, Issei recites the incantation, after which the Boosted Gear announces "Cardinal Crimson Full Drive!"
Super Gigantic Balance BreakerEdit
Super Gigantic Balance Breaker (超巨大禁手) is a form Issei attained in Volume 12 by receiving Great Red's help, in which Issei reproduces the size of Great Red which he uses to destroy Jabberwocky, a monstrous beast created by Annihilation Maker. In this form, he gains highly destructive powers such as the forbidden and sealed power of the Longinus Smasher, an attack that can cause an area in the Underworld to disappear without a trace.
Diabolos Dragon (Ｄ×Ｄ, Diaborosu Doragon) is a form that is exclusive to Issei. This is due to the fact that his body is made from Great Red's flesh, which enables Issei to temporarily borrow Ophis power. In this form, the armor becomes "organic" and changes shape and color from pure crimson to crimson and black. Additionally, this form gains a total of four wings, each one containing a cannon. Diabolos Dragon grants Issei Ophis's power of infinity, enhancing him to the point that he was easily able to overwhelm Rizevim Livan Lucifer, even with his Sacred Gear Canceller. Issei can use a finishing move called the Infinity Blaster, a move using all the cannons hidden in its wings. The Infinity Blaster is so powerful that the blast left Rizevim injured to a extent that his body was almost fatally damaged. According Rizevim, Diabolos Dragon has similar features to the Juggernaut Drive without the ominous aura and after his defeat he speculated that Issei is on a level of a Super Devil. However, the time Issei can spend in DxD mode is very limited, and after the armor is released, Issei experiences immense pain throughout his entire body.
Crimson Extinct Dragonar (深紅の滅殺龍姫クリムゾン・エクスティンクト・ドラグナー lit. Death Scarlet Destroyer Dragon Princess): An alternate form of the Boosted Gear Scale Mail armor created by Rias and Issei. Issei uses his Red Wyverns and sync his aura with Rias' and the Wyverns that attaches onto herself to create her own version of the Scale Mail armor that fits her perfectly. The armor acts just like the original, enhancing Rias' abilities and giving her the ability to utilize Boost, Transfer, and Penetrate until she reaches her limit.
Crimson Destruction Dragonar: Xenovia's own variation of the Scale Mail armor, which she gained by syncing her aura with Issei's that uses his Red Wyverns to attach themselves onto her body which shifts into the form of armor. Like the original, it has all of the same functions of Boost, Transfer and Penetrate. This is noted to be similar to Rias' own Crimson Extinct Dragonar, yet different from it.
The Plate Mails are mindless mass produced puppet versions of the Boosted Gear Scale Mail created by Rizevim to serve as Trihexa's subordinates. Trihexa was also modified in order to reproduce more of them as reinforcements.
Divine Dividing Scale MailEdit
The Scale Mail of Divine Dividing used by Vali creates a White Dragon Armor with blue jewels that covers the body of the user. In this form, Vali can halve the power of his opponents any time he wishes after he touches them until reaching his limits, but at the cost of a large amount of stamina and magical power.
Empireo Juggernaut OverdriveEdit
Empireo Juggernaut Overdrive (白銀の極覇龍, Inperiaru Jagānōto Ōbādoraibu) is a new form attained by Vali in Volume 12. It changes the color of his armor to silver. It was first used against Pluto. This form does not consume his lifespan, but consumes stamina and magical power at a very fast rate, to the extent where just using it in a short fight against Pluto caused Vali to breathe heavily from exhaustion. According to Vali, his Empireo Juggernaut Overdrive can even reach Gods in terms of power output but he can't maintain this form for a long time due to the form's massive stamina consumption rate. Upon seeing this form in combat, Cao Cao speculated that Vali may have reached the Super Devil level.
To enter into Empireo Juggernaut Overdrive, Vali recites the incantation, after which the Divine Dividing announces "Juggernaut Over Drive!"
Diabolos Dragon (Ｄ×Ｄ, Diaborosu Doragon) is a form that is granted to Vali by Ophis in Volume 21. Just like Issei's Diabolos Dragon, this armor is organic and is a mix of silver and black. The power granted is immense, enough to allow Vali to defeat a Heavenly Dragon-Class opponent. In this form, Vali can use one of Albion's lost techniques, a lethal poison that affects everyone except for Ddraig, Ophis, and Great Red. The time this form can be sustained is very limited. Its finishing move is the Satan Lucifer Smasher.
- Scale Mail is the only Balance Breaker that can be used by more then one Sacred Gear.
- Cardinal Crimson Promotion is modeled after the ZGMF-X10A Freedom Gundam from Mobile Suit Gundam SEED.
- Divine Dividing Scale Mail's Wings of Light bears a heavy resemblance to Lancelot Albion's Energy Wings from Code Geass.