Seeking an heir, the Red Skull fathered a daughter with a washerwoman. The woman died in childbirth, and the Red Skull almost killed the child, angry that it was a girl. One of his followers, Susan Scarbo, convinced him not to, telling him she would raise the girl herself as her nanny. The Skull agreed and left the girl (now named Sinthea) to be raised by Scarbo, who indoctrinated her with the Skull's views as she grew up. The Skull returned when Sinthea was a child and put her in a machine that accelerated her aging until she was an adult and gave her superhuman powers.

After, as Mother Superior, Sinthea became the leader of a group called the Sisters of Sin; young orphan girls who were accelerated into adulthood and given powers by the Skull after being indoctrinated by Sinthea. The Sisters of Sin would have many run-ins with the Red Skull's nemesis Captain America before being de-aged when they entered a chamber designed to reverse the Skull's aging process to assault Captain America - who had suffered through the Skull's process and had become elderly - while he was using it to return himself to normal, and they were reverted to children at the same time Captain America was restored (she would later claim she was de-aged to the wrong age - but whether this is true, and in which direction, is unclear).

Later, Scarbo (now calling herself Mother Night), reformed the Sisters of Sin and became their new leader, while the de-aged Sinthea took the name Sister Sin.

Sinthea was later captured by S.H.I.E.L.D. and taken to their reeducation facility, where they attempted to reprogram her to be a "normal" American girl and gave her false memories to that effect. Later, the Red Skull was assassinated by the Winter Soldier under the orders of Aleksander Lukin, and one of the Skull's henchmen, Crossbones, broke into the facility and kidnapped Sinthea. Crossbones tortured Sinthea to break S.H.I.E.L.D's conditioning. After he succeeded, she entered into a relationship with him, and - with Sinthea now calling herself simply Sin - the two went on a killing spree. They later reunited with the Skull, now living inside the mind of General Lukin.

As the first part of the Skull's Master Plan, Sin disguised herself as a nurse after the Civil War while Crossbones sniped Captain America at the courthouse, even though it meant obeying her father and abandoning Crossbones to his fate. Sin then revealed to Sharon Carter that she was the one who had killed Cap.

While the Red Skull had control over Steve Rogers' body, Sin fought alongside Crossbones against the Avengers' forces. After Steve Rogers eventually regained control of his body, Sin was knocked unconscious. After the battle, and due to a subsequent explosion, Sin's face was left severely disfigured and scarred, leaving her a "red skull". Upon hearing the news, Norman Osborn quipped, 'Like father like daughter'.

Sin was institutionalized at the Kurtzburg Institute for the Criminally Insane. During a breakout/riot, she was approached by Helmut Zemo, who asks her to tell him how to kill Bucky Barnes. More recently, Sin was liberated from the asylum by Master Man who has proclaimed both his allegiance and affection to Sinthea as the new Red Skull: the heir to her (believed deceased) father's legacy. ^[1]

Fear Itself

After taking the Black Widow and Sam Wilson hostage, Sin sent one of her henchmen to disrupt the Trial of Captain America and send her demands - Bucky Barnes. After escaping due to the manipulative Doctor Faustus, James confronted Sin and Master Man and brashly attempted to foil her escape. After the escape Sin aligned herself once more with Baron Zemo to aid her to retrieve the Book of the Skull. Zemo rebuked her offer for permanent alliance and told him of the origin of the Hammer of Skadi. Betraying Zemo, Sin went on her own to retrieve the Hammer. Sin and her henchmen went to the stronghold of the Thule society housing the Hammer. After being deemed worthy, Sin went to revive her new master, the Serpent. She then lead an assault on Washington D.C., during which, she almost kills Bucky Barnes. Skadi soon reached New York, where she faced off against Steve Rogers, who returned as Captain America. There, she summons the Serpent, when The Avengers tries to take him down he brokes Rogers' shield. With the Serpent, she knocks out the team and they go away. At Oklahoma, she, the Worthy and the Serpent battles the Mighty and Captain America. She is taken down by Rogers, who is wielding the Mjolnir. After the Serpent is killed by Thor, her hammer is taken from her by Odin, as well as the hammers of the other Worthy.

Search for power

Suddenly, Sin wakes up in a hideout where strange people said they freed her from custody and they would help to find her hammer again.

Powers and AbilitiesEdit

Powers

As Mother Superior, Sin possessed a range of superhuman powers including telepathy, telekinesis, teleportation and intangibility. After she was de-aged, she apparently lost these powers completely - unlike the other "Sisters of Sin", whose powers were diminished but not eliminated upon de-aging. The reason for this discrepancy is unclear.

Now that she has the Hammer of Skadi, Sinthia has the powers associated with wielding an enchanted Asgardian weapon.

Power Grid ^[2]

* Higher ratings with Hammer of Skadi.