Arc-En-Ciel

Arc-En-Ciel is one of the Next Dolls created by Promestein. She was specifically designed to defeat Granberia, easily overpowering the cursed swordswoman. Interestingly, similar to Granberia, Arc-En-Ciel loves fighting and a good challenge. Her body was structured to be incredibly strong and durable, resulting her immense offense and defense capability, but this also gives Arc-En-Ciel a five-year long lifespan.

Biography
At the end of Chapter 2, after Ilias declares war and Promestein lays siege on the Monster Lord’s Castle, Arc-En-Ciel easily overpowers Granberia and mocks her, though Luka tries to deny this by saying that the chimera was only able to defeat the Heavenly Knight because Luka weakened her in a fight moments ago.

Continuing on in Chapter 3, after Luka defeats Cupid, Valkyrie, and Archangel Ariel, Alice tries attacking Promestein, the leader of the attack. Arc-En-Ciel steps in, but Promestein stops her as there are already countermeasures against the Monster Lord, much to the chimera’s dismay. After Promestein seals Alice as well as Luka’s powers and then move on to capture him, Tamamo suddenly shows up with Giganto Weapon who mows down the chimera forces, but is made of short work by Arc-En-Ciel, who is a bit disappointed by its frailty; Promestein reassures her that it used to be stronger a long time ago. Shortly afterwards, Tamamo scares the Chimera Beasts with her aura alone, prompting Promestein to call a retreat, much to Arc-En-Ciel’s dismay.

When the Four Heavenly Knights press forward to the Ivory Towers, Arc-En-Ciel ambushes her chimera counterpart. Granberia asks if Arc-En-Ciel if she's truly proud of her body, who boasts her strength, but Granberia thinks the opposite, as Arc-En-Ciel's body and power were merely handed to her and therefore lacks the potential to grow and strengthen on her own. The chimera sternly denies this until Granberia resorts to using Luka's skill: Quadruple Giga. Arc-En-Ciel then admits that being infused with a warrior's soul only brought her pain, having longed to strengthen herself on her own, but now knows that it is impossible. Arc-En-Ciel then finds salvation in Granberia's attack, although she wished to fight Luka, but she no longer desires anything anymore and dies peacefully.

Monsterpedia Entry
"A Next Doll, one of the strongest Chimeric Monsters created by Promestein. Boasting overwhelming physical ability, she was created to counter Granberia. Her body was improved upon with muscle tissue strengthening, ultra-fast synapses, metabolic over limit through magic, and skin reinforced with nano-carbons.

''As a result, her strength, agility, and defense are all unmatched by any force in the Heavens or surface world. The only apparent weakness is her incredible need for energy to maintain her body.''

''Due to the intense strain on her own body, her lifespan is extremely short. Her life is believed to be maxed out at five years, at the most."''

Battle Overview
Arc-En-Ciel is fought by Granberia, not Luka. After lowering Arc-En-Ciel's health by about a fourth, Granberia gains the ability to use Quadruple Giga to end her counterpart. Because it has the best damage/cost ratio, Vaporizing Rebellion Sword should be the only attack used until Granberia runs out of SP, in which normal attacking will suffice then.

If Granberia falls, Arc-En-Ciel leaves to rape Luka using her vagina until he dies.

Trivia

 * Her name is French for rainbow, though how this relates to her character or design is yet to be seen.
 * Another possible explanation for the name is a degeneration of the word Archangel which is, when said, pronounced as Arc-En-Ciel.