Olivier

Olivier (オリヴィエ) was Alpha and Beatrix's ancestor and one of the Three Heroes who defeated the demon Diablos, known as the "Elf Hero". In reality, however, she was a pawn of the Cult of Diablos, being a survivor of their experiments, tasked by them with defeating the demon for their own ends. Her signature weapon is the Holy Sword.

Appearance
Olivier is described as a beautiful, gallant, almost divine even, figure of a woman warrior. Her appearance looks like a mirror image of Alpha and Beatrix.

She carries some kind of light blue magical talismans with gold accents on her forehead on the sides of her cheeks that form the appearance of a kind of helmet, which these are always attached to on her head (it is not known at the moment what function they fulfill).

In the light novel and manga, she is described as wearing beautiful emerald green armor with gold accents and a cape on her back, wearing a beautiful light blue skirt gold and black accents, black gloves with white accents, metallic boots and carrying a powerful sword made by the cult for her. While in the anime, she wears a white robe that covers almost her entire body to below her knees without any footwear with a prototype magic sword.

Personality
It's unknown what her real personality was, but Alpha's description of her implies that she had a great sense of justice as she believed defeating Diablos would save the world.

However after being sealed inside the Sanctuary for centuries, she had been reduced to an emotionless state, possibly forced to serve the Cult of Diablos.

Synopsis
Centuries ago, originally Olivier was a normal elf until she was kidnapped by the Cult of Diablos, to perform an experiment with her and all the other children, boys and girls alike they had kidnapped and collected to implant Diablos Cells, in an attempt to create powerful soldiers to fight the Demon King Diablos. The experiments resulted in almost failure, since most of the children ended up dying, and a small group of girls survived because they could not tolerate the blood of the demon in their veins.

Luckily for the Cult, 3 girls survived the experiments, whom turned out to be an Elf, a Beastkin and a Human, Olivier was one of the other 2 surviving individuals. The cult carried out more experiments to make them stronger and powerful, creating weapons and equipment for them so that when they were adults and ready, they would go fight the Demon King Diablos.

It was historically recorded that years later, Olivier already prepared along with the other two heroes, which is the Beastkin hero Lili and Human Hero (Freya; WN Only) went to exterminate the demon Diablos by order of the Cult, which resulted in the demon's defeat. During the battle, Olivier managed to cut off the demon's left arm with her sword, which was then sealed in the Sanctuary. In the end, she and the other two heroes were cursed by Diablos so that their descendants would be possessed with rotten bodies.

However, the truth was, Olivier was one of few people who are compatible with Diablos Cells. Hence, she was tasked by the Cult to gather more cells. Moreover, the Cult has already manipulated historical records globally and misgendered Olivier as a man, so that no one would be able to find out the real facts and try to investigate the truth.

In recent years, the Wandering Swordsman Venom managed to summon her via "Goddess's Trial" at Lindwurm but Olivier won the match.

Sanctuary Infiltration
During the infiltration of the Holy Ground, the group consisting Alpha, Delta and Epsilon managed to infiltrate the Sanctuary with the help of their lord Shadow, along with Beta (disguised as Natsume Kafka), Rose, Alexia, and the Acting Archbishop Jack Nelson who was held as a hostage. There, Alpha reveals the truth of everything as well as her relation to Olivier, and how Olivier is misgendered as a man, but in reality, is a woman and how the cult distorts history. Later Nelson reveals his true identity and tries to kill everyone, but Delta and Alpha manages to confront him without problems.

During the confrontation, Olivier is summoned as a mindless puppet with great magical power by Nelson to eradicate the members of Shadow Garden. But, they retreat before Olivier starts fighting them as Alpha dragging Delta away who was in battle euphoria, after having defeated more than a hundreds of Nelson's magical copies.

Later, Olivier is ordered by Nelson to kill Cid who was there along with Aurora's ghost. Cid manages to dodge her deadly strike, after receiving multiple wounds on his body. During the fight, numerous copies of Olivier appears, and in the end, he receives a fatal wound from the real Olivier. Cid who planned to get impaled by the real Olivier takes this moment to strangle Olivier's neck and gets rid of the copies. Then he destroys the entire Sanctuary together with Olivier and Nelson with his atomic move.

Powers & Abilities
Being one of the three survivors of the Cult of Diablos' experiments with the implanted cells of the Demon Diablos, it can be assumed that Olivier was considerably the most powerful individual, making her the most strongest weapon of the Cult, since she was able to defeat the demon king and seal it. Shadow himself noted that the projection of Olivier summoned by Nelson paled in comparison to the real deal.

Trivia

 * Because the Cult misrepresented history worldwide, both Olivier and his companions are treated as Men, instead of Women.
 * Interestingly, despite the fact that statues of the Heroines were made in their male form, the cultists keep a few silhouettes of them as they really look, this is seen when they enter the Shadow Garden, enter the Sanctuary and see the female statue of Olivier, and Lili memory appears to protect the right arm of Diabolos, under the royal academy of Midgar.
 * Until now, Olivier's lineage is the most numerous compared to the other two heroes, which is ironic, since Olivier an elf, like her race, should not have so many offspring due to their low birth rate.
 * It is speculated that the Cult of Diabolos forced her to have more offspring with her own and other races, such as humans and dark elves in order to harvest more blood from the heroes, since they had the blood of the Demon Diabolos running in their veins.
 * Olivier's descendants were most likely discarded by the Cult of Diabolos immediately, as they contracted Demon Possession at a very early age. They could not use their blood to speed up the Demon Diabolos revival. Therefore, they prioritized the descendants of the other two heroes, but the elves are still kept under surveillance in case one appears without possession.
 * Until now, during the "Goddess's Trial", the other two heroes, Lili and (Freya; WN Only) have not been summoned. The only one, so far to be invoked was Olivier.
 * In the anime, Olivier apparently is seen smiling briefly after Cid unleashed the "I Am Atomic! All Range Attack!".