Black Widow

Natalia Alianovna "Natasha" Romanoff, also known asBlack Widow, was one of the most talented spies and assassins in the entire world and a founding member of the Avengers. Originally an agent of the Soviet agency for foreign intelligence, the KGB, she later became a member ofS.H.I.E.L.D., the international counter-intelligence agency. Having extensive mastery in martial arts and armed with herWidow's Bite, Black Widow became one of S.H.I.E.L.D.'s most efficient agents. During one mission, she was sent undercover into Stark Industries to watch Tony Stark due to fears that he was dying. During this mission, Romanoff assisted Stark with defeating Ivan Vanko's terrorist plots against him.

When Loki declared war on the Earth, Black Widow was recruited into the Avengers as her friend Clint Barton had just been taken hostage by Loki and used as a pawn against the team. Romanoff assisted in recruiting Stark and Bruce Banner into the team while they tracked down and attempted to capture Loki, eventually saving Barton from his grasp. Once Loki's entire plan had been uncovered, Romanoff joined the team during the Battle of New York and was instrumental in destroying the portal over the city which had been created by the Tesseract, effectively ending the entire invasion while Loki was defeated and captured.

In the wake of the Avengers successfully defeating Loki, Romanoff had continued her work with S.H.I.E.L.D., this time working with Captain America. While working together, Romanoff and Rogers uncovered a conspiracy following anassassination attempt on Nick Fury, which had eventually led to them discovering that HYDRA had somehow been infiltrating their entire organization. Despite the efforts of theWinter Soldier to stop them, Romanoff helped exposeAlexander Pierce's evil schemes to the world, which also resulted in all of her own morally dubious history being revealed. As a result, Romanoff was forced into dropping off the grid again to begin rebuilding her cover.

Romanoff eventually rejoined the Avengers, working to bring down various HYDRA cells across the world and assisting in the capture of their leader, Baron Wolfgang von Strucker. However, before she could form a romantic relationship with Banner, the rogue artificial intelligence Ultron was created by Stark and Banner, forcing Romanoff and the rest of their team to join together and defeat him. Despite being captured, Romanoff was able to inform the team of Ultron's location onSokovia, resulting in a final battle in which the Avengers had defeated Ultron once and for all. Unlike most members of the original Avengers, Black Widow remained a member while forming the second incarnation of the team.

As many of the governments of the world had demanded the Avengers to sign the Sokovia Accords in the wake of their recent battles, Romanoff agreed to their terms and signed the Accords. She later joined Iron Man in a fight against Captain America due to his disagreements with the Accords and his criminal activities with the Winter Soldier who Rogers was attempting to protect. As the two Avengers' factions fought against each other, Romanoff betrayed Iron Man's team in order to assist Captain America to find the instigator of the team's fight. As a result, Black Widow had to escape from the government for aiding her old friend, while being on the run, Romanoff soon joined the fugitive Rogers and Wilson in stopping terrorists.

When the threat of Thanos approached Earth, Romanoff, Rogers, and Wilson protected Vision who had the Mind Stone, which Thanos was after. They later defendedWakanda from the attack and managed to kill all of Thanos' forces but unfortunately Thanos effortlessly overpowered Romanoff and the other heroes when he personally came to Wakanda and destroyed half of all life in the universe with the assembled Infinity Gauntlet, with Romanoff being one of the survivors.

After meeting Captain Marvel, Romanoff was part of theAmbush on Thanos in a try to retrieve the Infinity Stones and undo the Titan's snap, with no success.

Sometime later and after 5 years, Widow leads the Avengers alongside Captain America, now formed by Okoye, Rocket,Nebula, War Machine and Captain Marvel.

In order to undo the Decimation, the remaining Avengers split up in teams to retrieve all Infinity Stones from an alternate timeline. Romanoff was sent to retrieve the Soul Stone onVormir with Hawkeye. Having been told by Red Skull a sacrifice was required for the Stone, she and Hawkeye fought to be the one sacrificed, ultimately resulting in the both dangling off a cliff and Romanoff on the lower end, holding onto Hawkeye's hand. Romanoff then shakes herself loose, leading to her death in exchange for the Soul Stone.