Karl Fei-Ong

Karl Fei-Ong (Carl in the English dub) is one of Diva's chevaliers and a member of Cinq Flèches. He is the chairman of Lycee de Cinq Flèches, a renowned girls' high-school in Vietnam. He is also known as the Phantom.

Personality
Karl appears to be the outcast of his group. He frequently works alone, rarely talks to the other chevaliers and is often left out of important meetings. The cause of this rejection is hinted at in the anime: like all of her chevaliers Karl loved Diva deeply.

Although usually calm, Karl can be violent and obsessive, bordering on mental instability. His manic behavior stems from being used as a guinea pig in the Delta Project, repeatedly having his limbs removed and replaced and also being abandoned by Diva and trying to fill the loneliness which is why he turned his attention to Saya.

Diva
He tried to steal Diva away and keep her as his own. This undoubtedly was the cause of the rift between him and the other chevaliers, especially Amshel, whom he seems to fear.

Solomon
Solomon is Karl's only friend who displays any sympathy towards him. This sympathy however seems to be the result of Solomon's own guilt - not only was he the one who tricked Karl into becoming a chevalier, he also aided in his death. Although Karl is rarely involved with his brother's meetings Solomon phones him to keep him updated. Karl and Solomon are briefly seen "playing" together at the end of Episode 29 - Karl pretends to attack his brother with his new arm, but Solomon is much too quick and easily catches him by the wrist.

Amshel
In complete contrast to Solomon, Karl fears Amshel, probably because the organized the many operations performed on him. Amshel intentionally antagonizes Karl, noticeably by insisting James kill Saya despite the fact Karl volunteered first. Later it is revealed that he does this to deliberately provoke Karl into chasing after her, giving him an excuse to kill him.

James
Like Amshel James appears to have nothing but disdain for Karl, characterizing him as careless or reckless, and seeing his death more as a convenience than a loss to them.

Nathan
Interaction between Nathan and Karl is non-existent.

Origin
In 1917, Amshel Goldsmith chooses Karl Fei-Ong to use as a test subject for their new Delta project. He and Solomon Goldsmith introduce Karl to Diva in Germany. When he meets her, he requests her to turn him into a chevalier.

Karl's body is heavily modified by Amshel's experiments, including having the arm Saya destroyed in Vietnam in 1972 replaced with a spiked arm. His traumatic past, Diva's inability to give him the love he sought, and forced conversion seems to have left Karl severely mentally unbalanced. However, Solomon, the only one who could calm Karl's mania, believed Karl's problems stemmed from his being lonely and not seeing that Solomon was always there and watching over him.

In Vietnam
He is the chairman of an all-girl's school in his native Vietnam, where he is respected by both teachers and students. The girls themselves do not seem to fear him - they are polite and he is polite in return. Disguised as his alter ego "The Phantom", Karl kidnaps girls that look like Saya in his desire to see her again to finish their fight; before the girls went missing they were all given a blue rose. It's not clear whether he based "The Phantom" on the legend or whether the legend is based on him.

After finding Saya again, Karl becomes completely obsessed with killing her. He considers Saya his hated enemy, his beloved soul mate, and his only reason for living.

During the Red Shield's investigation in the Vietnamese jungle, they discover a secret farming facility owned by Cinq Flèches under the management of both Karl and Solomon. Karl leads an attack on the group, which causes several casualties. Saya later fights Karl, which results in Karl losing his leg in the process and being forced to retreat.

Breaking Shield
Karl finally gets his longed attention from Diva when she requested him to bring her "that boy," Karl (dressed as The Phantom) brings Diva to Red Shield's HQ without Amshel's authorization and begins killing all of the Red Shield's operatives. He encounters Saya, but Hagi distracted him long enough for Saya to escape. Karl escapes the ship along with Diva and manages to wound Joel with his spikes, which would cause him to be permanently crippled.

Death
While in London, he steals the Corpse Corps from Amshel after being outraged when James was given the orders to kill Saya instead of him and went after her while she was at Glay's home. He planned to die together with her by drinking all of her blood. Solomon, who'd come after him at Amshel's request, cuts off Karl's arm freeing Saya's sword arm. Realizing she has too much to live for, Saya stabs him by impaling her own body. With her sword coated in her blood, Karl crystallizes and is destroyed. Solomon mourns his death and tries to explain Karl's actions.

Powers and abilities
Enhanced Strength: Like other chevaliers, Karl has enhanced strength.

Transformation: In his true form, his original power was to make a blade from his hands. After having his right arm replaced by Amshel with a spike arm, he gained the Schiff's ability to crystallize his blood and fire it from his arm. He is also capable of flying as he possesses a pair of wing each located underneath his arms.

Healing: Like all Chiropterans, he has great healing abilities, recovering from stab and gunshot wounds within moments.

Telepathy: Stated in the light novel, Chiropterans have the ability to sense other Chiropterans. Karl's ability with this is greater than James Ironside.

Weakness: His weaknesses, like all chevalier, include Saya's blood and, if Amshel was telling the truth, decapitation and complete incineration of the body. It is unknown whether or not that he, like James, could contract the Thorn.

Manga
In the manga adaption, Karl's appearance and mannerisms are completely changed. He's more childlike and is stated to look several years younger than Riku, who is fourteen. Karl is the only one besides Amshel that Diva cares for. After losing his arm during the fight at Vietnam with Saya, he is forbidden from seeing Diva again and loses his status as a chevalier, becoming a living experimental subject for the next generation of chiropterans. He is then renamed "Charles" by Amshel. His renewed form is later killed by Saya.