Sif

"I've got this completely under control!" "Is that why everything is on fire?!"

- Sif and Thor

Sif, also known as Lady Sif, is an Asgardian adventurer and warrior. Once worshiped by the Vikings as the Norse goddess of war, she is a good friend of the Asgardian prince Thor and the Warriors Three. When Thor almost provoked a war with the Frost Giants and ended up powerless on Earth, Sif and her friends disobeyed the orders of their new king Loki and went to Earth to save their friend. Thanks to them Thor returned to Asgard and Loki's reign of terror ended.

Later, along with her friends, Sif bravely fought against the Marauders, the intergalactic pirates who pillaged the unprotected realms of the universe. After the Second Dark Elf Conflict, she was sent to Earth and successfully captured one of Asgard's most dangerous renegades, Lorelei. Shortly after returning Lorelei to Asgard, Sif suddenly reappeared on Earth, suffering from a mysterious case of memory loss, and was found by Phil Coulson's S.H.I.E.L.D.

Early Life
"And who proved wrong all who scoffed at the idea that a young maiden could be one of the fiercest warriors this realm has ever known?" "I did!" "True, but I supported you, Sif."

- Thor and Sif

During her early years, Sif's great talents as a warrior were not appreciated by many because she was a woman. Thanks to her friend Thor, who believed in her capabilities, Sif became one of the most appreciated warriors of Asgard, along with the Warriors Three, Loki, and Thor himself.

Sif was also romantically involved with a warrior named Haldor, who was later enthralled by the sorceress Lorelei. The event led to Haldor's death, creating a deep hatred between Sif and Lorelei.

Jotunheim
"This isn't like a journey to Earth, where you summon a little lightning and thunder, the mortals worship you as a God! This is Jotunheim." "My father fought his way into Jotunheim. Defeated their armies and took their casket! We would just be looking for answers." "It is forbidden!"

- Fandral, Thor, and Sif

When the Frost Giants of Jotunheim interrupted Thor's coronation ceremony by attempting to steal the Casket of Ancient Winters, Sif, Loki, and the Warriors Three were convinced by Thor to attack Jotunheim, to find those responsible. While in Jotunheim, Sif fought alongside her friends against an army of Giants led by Laufey himself, and managed to slay many of them, but was forced to flee when they were outnumbered. Eventually, the team was saved by Odin himself, who intervened to prevent their killing. Helpless, Sif witnessed Thor's banishment to Earth.

Disobeying the King
"We all know what we have to do." "We must go. We must find Thor." "It's treason." "To hell with treason. It's suicide."

- Sif, Hogun, Fandral, and Volstagg

Some days later, Sif persuaded the Warriors Three to ask Odin to recall Thor back home, but when they arrived in the throne room, they found Loki sitting as the new ruler of Asgard, as a substitute to Odin who had fallen into the Odinsleep. Loki denied their request to call his stepbrother back, but they decided to ignore his order and to go to Earth anyway.

Battle of Puente Antiguo
"You know I can't go home. My father is...dead because of me. I must remain in exile." "Thor, your father still lives."

- Thor and Sif

Heimdall agreed with them and opened the Bifrost Bridge for them, and the four Asgardians arrived on Earth, in New Mexico. Here, they easily spotted Thor, and found out that he had been tricked by Loki's lies. Shortly afterwards, The Destroyer was sent to Earth by Loki to kill Thor and the other Asgardians, and Sif engaged it in the battle with her friends. While the Warriors Three bought her some time, Sif climbed a rooftop and attacked the Destroyer from above, piercing its throat with her Double-bladed Sword. Immediately after, however, the Destroyer regenerated itself and almost vaporized her with its energy blast. Sif fled with her companions, leaving Thor, who claimed to have a plan, behind, but only to assist his sacrifice and his rebirth in his divine form.

Return to Asgard
"My Queen, I'm so sorry for your loss. How is he?" "He mourns for his brother. And...he misses her, the mortal."

- Sif and Frigga about Thor

Back in Asgard, Sif brought Heimdall to the Restore Room, while Thor defeated Loki once and for all. Along with other Asgardians, Sif celebrated Odin's return to the throne and Thor's return to the realm, participating to a gargantuan banquet.

Marauders, Dark Elves, and Loki
"Betray him, and I will kill you." "Nice to see you too, Sif.""

- Sif and Loki

Sif fought with Asgard's armies, the Warriors Three, and Thor to regain control of the Nine Realms after they were thrown into turmoil following the destruction of the Bifrost Bridge. She fought in the battle against the Marauders on Vanaheim. During the fight, she saved Thor's life when the Marauders attempted to fire a missile at his head by blocking it with her shield. When Thor and the Warriors Three celebrated their victory against the Marauders, Sif saw Thor leave and stand alone outside the traven, Sif attempted to renew a romantic relationship with Thor, secretly somewhat jealous of his love for Jane Foster. However Thor kindly refused and left.

She later defended Asgard from Malekith and the Dark Elves during the Sacking of Asgard. As she and a squad of Asgardian soldiers went to defend Asgard, Sif saw Jane escape to safety with Frigga. Shortly thereafter, Sif aided Thor in freeing Loki and getting himself, Loki and Foster out of Asgard and into Svartalfheim. As Thor, Jane and Loki made their way to an abandoned Dark Elf ship, Sif held back the Asgardian guards attempting to capture them. Before they left however, Sif made sure that Loki knew that if he betrayed Thor, she would kill him.

Transfer of the Aether
"I can assure you it will be absolutely safe here in my collection." "See that it is."

- Collector and Sif After the Battle of Greenwich, the Aether was recovered from Svartalfheim and contained. On Odin's orders, Sif and Volstagg delivered the Aether to the Collector on Knowhere, saying that it was unwise to keep two Infinity Stones in the same place.

Hunt for Lorelei
"You are of S.H.I.E.L.D.?" "Yeah...?" "I am Lady Sif, of Asgard. Your world is in grave danger."

- Sif and Grant Ward

During the Sacking of Asgard, Lorelei escaped from the Asgardian Dungeons, and Sif was tasked by Loki, masquerading as Odin, with capturing her. Sif pursued her to Earth, where she was immediately greeted by Phil Coulson's team of S.H.I.E.L.D. agents.

She was taken to the Bus, where she expressed shock to discover that Coulson was still alive, having heard from Thor that he had perished at the hand of Loki. She agreed to obey his wishes and not inform Thor that Coulson was alive. Sif told the team that she was hunting Lorelei, and desired their help in locating her. Together, the two parties tracked Lorelei to Rosie's Desert Oasis, but, in the ensuing confrontation, Lorelei managed to take control of Agent Grant Ward. Additionally, during the battle, the Asgardian Collar that Sif had brought to gag Lorelei and break her hold on her victims, was damaged, leaving the team no recourse short of death to break her spell. Sif gave the collar to Leo Fitz hoping that he would be able to repair the damage. While Skye attempted to track Lorelei and Ward, she talked with Melinda May about her own experiences at the hand of Lorelei, warning May that Ward was no longer the man she had known.

After Skye located Ward in Las Vegas, Sif visited the suite where he and Lorelei had stayed, but did not capture them. She returned to the Bus to discover that Fitz had fixed the collar as well as that Ward and Lorelei had returned to the Bus and taken control of Fitz who locked Sif in the Cage and opened the airlock. Though she was ejected from the Cage, she managed to hold on to an edge of the plane until Agent Coulson opened the airlock and let her back in. Inside, she discovered that Lorelei had taken her sword and the two dueled, the fight ending when Sif forced the collar back on Lorelei who had been taunting her about what she had done to her lover Haldor. After thanking Coulson and his team for their help, Sif departed with Lorelei and returned to Asgard.

Amnesia
To be added

Personality
Being the only female warrior in Asgard, Sif is very proud and always eager to prove herself. She's the closest of friend with Thor and the Warriors Three, and she's an honorable warrior on the battlefield. She often is independent and uneasy in following the orders. She has a surprisingly accurate knowledge of some advanced human technology and, unlike most other Asgardians, does not view mortals as lesser beings. Sif also harbors romantic feelings for Thor, being protective of him, jealous of his love for Jane Foster and showing a willingness to aid him even if it means treason. Despite her desires for Thor, she was ready to help in his mission to save Jane, showing a great level of selflessness and honor.

Powers and Abilities
As an Asgardian, Sif possesses superhuman physical attributes such as strength, stamina, speed and reflexes, and she's an incredibly skillful fighter. She wields a double edged sword, which she uses perfectly, either separate as two blades or a single long sword staff.

Powers
Sif possesses all of the various superhuman attributes common among the Asgardians. Sif possesses superhuman strength, speed, agility, reflexes, durability, and is extremely long-lived.
 * Asgardian Physiology: As an Asgardian, Sif has superhuman abilities.
 * Superhuman Strength: Like all Asgardians, Sif is super-humanly strong and possesses greater physical strength than the average Asgardian female. She was able to hold her own against many stronger foes. Sif was able to, with one push from her foot, move a very large RV several hundred feet.
 * Superhuman Speed: Sif is capable of running and moving at speeds much greater than that of even the finest human athlete.
 * Superhuman Stamina: Sif's musculature produces considerably less fatigue toxins during physical activity than the musculature of a human being. She was able to hold on to the top of the Bus for an extended period of time, while the plane was in the air, traveling at full speed.
 * Superhuman Dense Tissue: Sif's bodily tissues are denser than the tissue of a human. As a result, Sif is actually much heavier than she appears. This increased tissue density also contributes somewhat to her physical strength.
 * Superhuman Durability: Sif's body is much more resistant to physical harm than the body of a human being. She is capable of withstanding great impact forces from Frost Giants and the Destroyer, and exposure to extreme temperatures and pressures of Jotunheim.
 * Regenerative Healing Factor: Despite her body's resistance, Sif can be injured like any other Asgardian. However, her metabolism enables her to rapidly regenerate damaged bodily tissue with greater speed and efficiency than a human being is capable of. Injuries such as slashes and punctures can fully heal within hours, whereas broken bones can heal within a few days. However, she isn't able to regenerate severed limbs or missing organs. After Sif and the Warriors Three took a severe beating from the Destroyer, she returned to Asgard looking no worse for ware.
 * Extended Longevity: Like all Asgardians, Sif ages at a rate that is much slower than that of a human being. However, Asgardians aren't completely immune to aging, as she is several hundred years old by human standards.

Abilities

 * Master Combatant: Sif is an excellent combatant and has received extensive training in unarmed combat and swordsmanship. Asgard's greatest warrior Thor comments that Sif proved "all wrong who scoffed at the idea of a young maiden being one of the fiercest warriors." Also Lorelei comments that "the graves of Asgard's enemies are filled with men who underestimated Sif."; this states that Lorelei felt Sif was a dangerous threat to her, granted that she was just as skilled as her. She was able to hold her own in battle against legions of Marauders and Frost Giants.

Equipment

 * Double-bladed Sword: Sif's signature weapon of choice is a double-bladed sword. One of the two blades is retractable, allowing for Sif to fight with a single-blade.
 * Shield: Sif almost always carries around a shield, providing defense in battle. The shields are made up of a strong Asgardian metal capable of deflecting gunfire.
 * Armor
 * First Set: Sif’s first armor consisted of a collared red mini-dress over chain mail and was covered with silver plating. The silver plating was in the shape of a deep-scoop shirt with her upper chest covered by silver chain mail. It also was in the form of a belt and shoulder pads. Her right upper arm had a silver bracelet and her left arm had a red band around it. Her hands and lower arms were covered by red fabric and her arms had arm-bracers. Sif wore dark-grey pants and detailed black boots. This armor was worn with a pale greyish-purple cloak during her visit to Jotunheim.
 * Second Set: Sif’s second armor was silver and dark red. Her armor wore a red leather dress that continued down her torso ending in a multi-paneled mini-skirt. Over her dress, she wore silver armor plates that ended right above her cleavage. Her neck was covered by a sheer material. Sif also wore black pants under her skirt and brown and silver knee high boots.

Allies

 * Asgardians
 * Odin - King
 * Frigga † - Queen
 * Thor - Friend
 * Heimdall
 * Warriors Three - Friends
 * Fandral
 * Volstagg
 * Hogun
 * Haldor † - Former Lover
 * S.H.I.E.L.D. (First Incarnation) - Allies
 * Coulson's Team
 * Phil Coulson
 * Grant Ward
 * Melinda May - Friend
 * Leo Fitz
 * Jemma Simmons
 * Skye

Enemies

 * Loki - Friend turned Enemy
 * The Destroyer
 * Frost Giants
 * Laufey †
 * Marauders
 * Dark Elves
 * Malekith †
 * Algrim †
 * Lorelei - Nemesis

Video Games Only

 * Fire Demons
 * Ymir

Appearances

 * Thor, The Mighty Avenger
 * Thor
 * Thor: The Dark World Prelude
 * Thor: The Dark World
 * Guardians of the Galaxy Prequel Infinite Comic
 * Agents of S.H.I.E.L.D.
 * Season One
 * Yes Men
 * Season Two
 * Who You Really Are

Trivia

 * In the comics, Sif is Thor's lover and main love interest, not just a friend or a teammate, being a direct adaptation of, where Sif is the wife of Thor. Her feelings for Thor are hinted in the end of the first film when she looks at him talking with his father, and also when Lorelei taunts her during their fight.
 * Also in the comics, Heimdall and Sif are brother and sister. Although this relationship has not been explored in the movies, concept art exists of a black Sif, confirming that this relationship was originally propped for Thor.
 * In the non-canon comic Captain America & Thor: Avengers! Sif helps her friends to free Fandral who is captured by the Dark Elves led by Queen Alflyse.

Behind the Scenes

 * In Thor, Agent Garrett referred to Sif as Xena from the 1995-2001 television show . The portrayer of Xena in the show, Lucy Lawless, appears in the first episode of the second season of Agents of S.H.I.E.L.D., while Sif appeared in the first season.