Crossbones

"There are no prisoners with HYDRA, only order. And order only comes through pain. Are you ready for yours?" "Man, shut the hell up!"

- Brock Rumlow and Sam Wilson

Brock Rumlow was a HYDRA sleeper agent inside S.H.I.E.L.D. and the STRIKE team leader. He is a world-class hand-to-hand combatant with an extensive experience in street fighting techniques, various martial arts and military combat techniques.

Early Life
Brock Rumlow was an agent of S.H.I.E.L.D. who, over time, was tasked with leading STRIKE. As the leader of STRIKE team, he was often partnered with Captain America and the Black Widow after the former joined S.H.I.E.L.D. During his career, he became a double agent for HYDRA, a terrorist organization with the goal to create the fascist New World Order.

Zodiac
One operation saw Rumlow assisting in the recovery of the stolen Zodiac weapon and the apprehension of the terrorists that stole it.

During one of their missions together, Rumlow, partnered with Rogers and Romanoff, was able to stop a terrorist group led by a man only known as Baker from launching an attack with the stolen Zodiac weapon in Chicago.

Rogers and Rumlow defeated most of the terrorists while Romanoff took care of Baker himself. She was not able to defeat him; however, after his men had fallen, he could not defeat the three of them, so Baker tried to flee by throwing himself from a window.

As Captain America was unwilling to let Baker escape with the Zodiac, he too jumped off the Skydeck and struggled with Baker in mid-air. Unwilling to die in the fall, Baker released the Zodiac to Rogers and activated his parachute, while Rumlow snared Captain America in mid-air back on the Skydeck with a grappler arrow.

The Lemurian Star
"Thanks." "Yeah, you seemed pretty helpless without me!"

- Captain America and Brock Rumlow

Agent Rumlow led STRIKE, Captain America, and Black Widow on a mission to recapture the Lemurian Star, a S.H.I.E.L.D. ship hijacked by Georges Batroc and his pirates. Rogers left the Quinjet first, when Jack Rollins questioned if he had jumped out without a parachute, Rumlow confirmed that he had. Rumlow and STRIKE team joined Rogers moments later and killed Batroc's subordinates and rescued the hostages, including Jasper Sitwell.

HYDRA Uprising
"Whoa, big guy, I just want you to know, this isn't personal!" "It kinda feels personal."

- Brock Rumlow and Captain America

A few days later, Rumlow and the STRIKE team attempted to capture Steve Rogers inside an elevator, due to Rogers having been declared an enemy of S.H.I.E.L.D. by Alexander Pierce. However, Rogers soon became suspicious and gave the team a chance to escape; they refused and attempted to capture Rogers using Magnetic Handcuffs. After a brief fight, Rumlow and Rogers were the last men standing. Rumlow told Rogers the fight was not personal and attacked Rogers with his Taser Rods. Although he was able to momentarily gain the upper hand, Rumlow was quickly defeated when Captain America knocked him out. Rumlow led the ensuing manhunt against Rogers, tracking him to a mall in DC when he and Natasha Romanoff activated a hard-drive with a tracker on. Rumlow arrived at the mall and failed to spot the fugitives. Later, they were located at Camp Lehigh, where Arnim Zola's computer was located. Alexander Pierce destroyed the camp with a missile and Rumlow explored the area and discovered a pair of footprints telling him that Rogers and Romanoff had survived and escaped. Rumlow reported back to base and told them to call in the asset. Rumlow and STRIKE finally found and captured Steve Rogers, together with Natasha Romanoff and Sam Wilson on the streets of Washington, D.C. after they had had a prolonged fight with the Winter Soldier. When Jack Rollins attempted to execute Rogers by shooting him in the back of head, Rumlow noticed the news helicopter watching overhead and ordered him to wait. He then took them to a secure location to execute them, only to discover they escaped with help from Maria Hill. Rumlow and Jack Rollins escorted Alexander Pierce to a secure location to begin questioning the Winter Soldier, who was struggling to understand why he seemed to remember Captain America from a past life. Rumlow acted as Pierce's bodyguard, raising his gun when the Winter Soldier began to attack the people around him. Rumlow watched closely as the Winter Soldier was beaten and Pierce ordered his memories to be wiped once again so he could attack Rogers once again.

Battle at the Triskelion
"You're out of your depth kid!"

- Brock Rumlow to Sam Wilson

Rumlow made his way into the control center of the Triskelion to ensure the launch of the Helicarriers while Captain America revealed HYDRA's infiltration within S.H.I.E.L.D.. When Cameron Klein the technician in control of the launch sequence, refused to send up the Helicarriers, Rumlow threatened to kill him. Sharon Carter defended Klein by putting a gun to Rumlow's head. A gunfight between S.H.I.E.L.D. and HYDRA agents ensued, but Rumlow was able to get the Helicarriers in the air and escape. On his way through the Triskelion, Rumlow managed to kill several S.H.I.E.L.D. agents until he received a call informing him that Black Widow had attacked and captured Alexander Pierce. As he went to protect Pierce, Rumlow was attacked by Falcon. Rumlow prepared for a long fight and told him that the fight was going to hurt as HYDRA did not take prisoners. Falcon simply told him to shut up as they began to fight. As Rumlow gained the upper hand, he threw his opponent across the room while taunting him, but while doing this he did not spot the incoming Helicarrier which crashed into the building. He tried to flee but was soon knocked over by the crumbling building. Rumlow managed to survive despite being burned and crushed under Helicarrier rubble and was taken away by medics.

Personality
Rumlow was shown to be extremely loyal to HYDRA, as well as being slightly cocky, as when he saved Captain America aboard the Lemurian Star. He had a strong attitude, as well as a tendency to go to extreme lengths to do things, as when he threatened to kill Cameron Klein if he did not launch the Insight Helicarriers.

Abilities

 * Master Martial Artist: Rumlow is a formidable hand to hand combatant. He was able to evade the knifes thrown by one of the men in Baker's terrorist cell and easily defeat him, and to hold his own against Steve Rogers for the longest when the whole STRIKE team tried to capture him in one of the elevators in the Triskelion. He also dominated Sam Wilson in their fight and mocked him for being in a superior fighting level, as Wilson only hit Rumlow when he ambushed him.
 * Expert Marksman: Rumlow is a very accurate marksman skilled in sharpshooting, being able to, among other things, shoot a rope with a crossbow to catch Captain America to prevent him from falling from a building, or accurately land a single shot to a target's head while parachuting.

Weapons

 * Taser Rod: While attempting to capture Captain America, Rumlow and his STRIKE team used Taser Rods to weaken the super soldier and arrest him. However they quickly learned that the Rods were not strong enough to stop Captain Rogers and he escaped.

Allies

 * HYDRA
 * Alexander Pierce † - Leader
 * Jasper Sitwell †
 * STRIKE
 * Jack Rollins - STRIKE Subordinate

Enemies

 * S.H.I.E.L.D. (First Incarnation)
 * Nick Fury - Former S.H.I.E.L.D. Director
 * Maria Hill - Former S.H.I.E.L.D. Deputy Director
 * Sharon Carter - Former S.H.I.E.L.D. Colleague
 * Steve Rogers/Captain America - Former S.H.I.E.L.D. Colleague turned Enemy
 * Natasha Romanoff/Black Widow - Former S.H.I.E.L.D. Colleague turned Enemy
 * Baker
 * Georges Batroc
 * Sam Wilson/Falcon

Trivia

 * In the comics, Brock Rumlow is an agent of the Red Skull known as Crossbones, and became romantically involved with his daughter Sin. It has been confirmed that he will bear the moniker of Crossbones in Captain America: Civil War.
 * In Captain America: The Winter Soldier, Brock Rumlow wears equipment under his Bulletproof Vest that is meant as a reference to his attire in the comics.