When it comes to Deadpool, Colossus just doesn't know how to quit. While his laconic protégé Teenage Negasonic Warhead looks on—or, you know, just looks at her phone—he tries and tries to recruit Deadpool for the X-Men. But it's pretty clear that Deadpool's just not that into them.
Don't Stop Believin'
Colossus is too hardheaded to give up on Deadpool, though, and we're not just saying that because he's made out of "organic steel." Colossus believes that underneath all that sarcasm and gore, lies the heart of a hero. That's why he and Negasonic Teenage Warhead race down to the accident site to remove Deadpool from the situation.
He also believes that for Deadpool to behave the way he does is an abuse of his mutant abilities. When he shows up at the blood-and-guts-filled scene of the accident, he chastises Deadpool:
COLOSSUS: You've been warned before, Deadpool. This is a shameful and reckless use of your powers.
Colossus serves as a foil to Deadpool's twisted code of ethics. Where Deadpool is brutal and more than willing to play dirty, Colossus is noble and virtuous. He seems to truly believe in Deadpool and, while he may not agree with the madness of Deadpool's methods, he remains loyal to him. Case in point: he and Negasonic Teenage Warhead agree to serve as Deadpool's allies in the shipyard fight against Ajax. Even when Deadpool has Ajax dead to rights, Colossus has faith in Deadpool and considers him capable of doing what's right and sparing Ajax's life:
COLOSSUS: Four or five moments. That's all it takes.
COLOSSUS: Be a hero. Everyone thinks it's a full-time job. Wake up a hero. Brush your teeth a hero. Go to work a hero. Not true. Over a lifetime, there are only four or five moments that really matter. Moments when you're offered a choice, to make a sacrifice, conquer a flaw, save a friend, spare an enemy. In these moments, everything else falls away. The way the world sees us, the way we—
Deadpool shoots Ajax in the head. Colossus vomits.
DEADPOOL: You were droning on.
Of course, the fact that Colossus never gives up on the idea of Deadpool going straight means he's frequently the straight main to Deadpool's jokes. Negasonic Teenage Warhead, on the other hand, exists to fight, stare at her smartphone, and be thoroughly underwhelmed by Deadpool—and especially his sense of humor that skews heavily toward '90s pop culture. Deadpool is mouthy and manic in his middle-age; Negasonic Teenage Warhead is the uber-teen: unmoved and indifferent.
A Link to the Days of Future Past (and All the Other X-Movies, Too)
Colossus and Negasonic Teenage Warhead also play one other important role in Deadpool: They connect Deadpool to the X-Men and the greater Marvel universe. It's a running gag in the movie that these two B-level mutants were the best the movie studio could afford. (Okay, so Negasonic Teenage Warhead is more like a D-list mutant; no offense, girl.) Check out this jab Deadpool makes at 20th Century Fox when he stops by the X-Men's mansion to recruit Colossus and Negasonic Teenage Warhead:
DEADPOOL: It's a big house. It's funny that I only ever see two of you. It's almost like the studio couldn't afford another X-Man.
In typical Deadpool fashion, the pot-shots at Marvel and the X-Men don't stop there. He suggests that he had to perform, uh, favors for Wolverine in order to get his own movie, and when Colossus suggest that they go talk to Professor X, Deadpool calls out the X-Men films' complicated chronology:
COLOSSUS: Let us go talk to the Professor.
DEADPOOL: McAvoy or Stewart? These timelines are so confusing.
Colossus and Negasonic Teenage Warhead play a small role in Deadpool, but it's a multi-faceted one. They serve as Deadpool's conscience, his sounding board, and his sidekicks in both combat and comedy. Together, they're the Chewbacca to his Han Solo and the Patrick to his SpongeBob.