Friendships form in the funniest places. You would think that Deadpool and Captain America wouldn't be friends. Deadpool is a hyper-violent, hyper-talkative mercenary powered by pop culture references and the knowledge that he's in a comic book. Alternatively, Captain America is a hero of the oldest old school who has never seen a Star Wars movie. They might appear to be exact opposites, yet Deadpool and Captain America are two sides of the same coin, Steve Rogers is the result of a successful super-soldier program, a one-of-a-kind leader, and Deadpool was a guinea pig for the Weapon X Program who finds himself shepherding outcasts.

Though Captain America and Deadpool are exact opposites in nearly every aspect, the Sentinel of Liberty and the Merc With a Mouth had a canonical friendship spanning three years. Now, CBR is taking a look back at this unlikely pairing, how they met and what ultimately split them apart.

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HOW DID CAPTAIN AMERICA AND DEADPOOL MEET?

Deadpool Wolverine and Captain America with NK X-Men

For these heroes, friendship bloomed on the battlefield, when the Weapon Plus graduates Deadpool, Wolverine and Captain were abducted to a North Korean super soldier program/death camp in 2014's "Deadpool: The Good, The Bad and The Ugly" storyline by Brian Posehn and Scott Koblish.

Not wanting to create an international incident, Steve Rogers acknowledges that while liberating this camp cannot be a mission for the Avengers, it must be a job for Captain America. Furthermore, Deadpool has literal skin in the game, as not only is his DNA being utilized to create bootleg X-Men, but his family is being held in another camp.

The exact nature of Captain America and Deadpool's friendship is established through their dismantling of the camp. While Deadpool and Wolverine rig the underground laboratory with explosives, Captain America holds off the entire North Korean army above ground, granting Cap plausible deniability about his mercenary ally's mischief.

Though they successfully liberate the camp, Deadpool fails to save his family. As Wolverine and Captain America exhume a screaming Deadpool from a mass grave, a nigh-unbreakable relationship is forged between the nigh-unbreakable superheroes. Parting ways, Captain America considers Deadpool as not only a good soldier, but also a friend.

HOW DID CAP AND DEADPOOL BOND?

Deadpool with Old Man Steve Rogers Death of Wolverine

Deadpool and Steve Rogers bond over the then-dead Wolverine in 2014's Death of Wolverine: Deadpool & Captain America by Gerry Duggan and Scott Kolins. Deadpool and an elderly Steve Rogers raid an A.I.M. super-science facility, seeking a knife covered with Logan's blood.

After leveling the facility, Steve bequeaths the bloodied blade to Wade, entrusting him to destroy it, ensuring that their fallen friend won't be resurrected through comic book shenanigans to become another living weapon.

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For some time Deadpool runs non-lethal missions pro bono for the elderly Rogers, not complaining because "You have to follow the rules when your handler is Steve Rogers." After Deadpool successfully steals a can of Terrigan Mist, Steve drafts Deadpool into the Avengers' Unity Team in "The Night That Hell Froze Over" by Gerry Duggan, Ryan Stegman and Richard Isanove in 2015's Avengers #0.

Deadpool's purpose on the team is threefold: First, Deadpool is the token anti-hero, proving that anyone can be an Avenger. Second, Deadpool is the team's triggerman, handling the tasks that must be done but that the others won't do. Finally, Deadpool bankrolls everything, thanks to his newfound popularity.

HOW CAP AND DEADPOOL's FRIENDSHIP ENDED

Deadpool works for Steve Rogers Captain America

In the fallout of Civil War II, Deadpool lies to Captain America at Bruce Banner's funeral, claiming to not know the whereabouts of the AWOL members of the Unity Division in 2015's Uncanny Avengers #15 by Gerry Duggan and Pepe Larraz.

Discovering Deadpool's dishonesty, Captain America dishonorably discharges Deadpool from the team. Walking away from a devastated Wade, Cap twists the knife: "Once again... you were just another failed experiment." Moments later Cap disbands the team, explaining that its purpose of uniting X-Men with Avengers in the public eye is pointless if Captain America ends up back-stabbed.

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Despite this betrayal, Deadpool still worked for Steve Rogers, helping Captain America gun down an unarmed Captain America from the future in 2017's Deadpool #27 by Gerry Duggan and Scott Hepburn. Claiming that Agent Phil Coulson has gone rogue, Steve sends Deadpool after Coulson in Deadpool #31. Deadpool tags Coulson with a gut-shot, claiming "when Captain America says jump -- you jump."

Before Wade can realize the error of his ways, Captain America reveals himself as Hydra Supreme Commander, which technically makes Deadpool a Hydra agent. Shortly after that, this Captain America was revealed to be an imposter in the Secret Empire crossover. Despite that, Deadpool had always served as Captain America's living weapon. We even learn that the real Captain America drafted Deadpool into the Avengers to fill Logan's spot on the team.

Even though Cap once entrusted Deadpool to stop someone from making Wolverine a living weapon, Captain America used Deadpool as his own personal one-man army. After confronting Captain America about the imposter's actions, Deadpool deleted his memories of the friendship, along with several other months' worth of memories.