Sometimes, the studios managing the massive cinematic universes that dominate modern filmmaking throw a few characters into a project as a screen test to see which ones earn their keep. Other times, a character hits the screen organically in a supporting role and finds an audience ready and willing to see more.
Domino was created in the early 90s and introduced to the enormous X-Men universe by artist and co-writer Rob Liefeld, the same controversial creator who crafted Deadpool. She's never quite made the A-list, but she's been a fixture of cartoons and video games over the years. Her live-action debut came almost 30 years after her first appearance, and it deviated from the source in a few big ways.
For the uninitiated, Deadpool 2 sees the merc' with a mouth pitted against a threat he's convinced he can't take alone, so he undertakes the time-honored tradition of gathering a superhero team. X-Force, the slightly derivative team he puts together, is staffed almost entirely by unknowns who are killed off as quickly as they appear. The lone survivor, aside from Deadpool himself, is the member of the team that Wade most easily dismissed.
During the interview montage, Domino makes her entrance with immediately likable energy. She proclaims confidently that she was drawn to the event by fate, then argues with Deadpool about the merits of her supposed power. After she's made her entrance, things just seem to go her way. Domino is one of the biggest players in the film's action scenes. She's more than a sidekick, she's a dynamic ally with shifting motivations and a compelling narrative thrust. Even with limited screen time, Domino makes a stellar impression.
Performance is everything here. Domino has typically been portrayed as a fairly serious villainous character. Zazie Beetz takes the role into a realm of easy charisma and perfect comic timing. She's far from the comic book source material, but every change made by her and by the script is for the better. She's a great comic foil for Deadpool. While Wade can't take anything seriously, constantly undercutting his dramatic moments with a one-liner or a pop-cultural reference, Domino is a sardonic and confident figure. At his worst, Deadpool can feel like he's trying too hard, which makes Domino's effortless performance stand out and remain compelling. This is likely the version of the character that fans will remember, and she could be a perfect hero on her own, as well as part of a team.
Domino's power is a bit silly, and could easily be abused by a lazy writer, as Deadpool is quick to point out. With no effort on her part, Domino subtly alters probability in her favor, ensuring that just about everything goes her way. This doesn't make her infallible, but it does ensure that her elite skill-set is complimented on all sides by every element of the environment. Some adaptations of the comics have struggled with making that power interesting, falling back on her more simplistic combat skills.
The film finds easily the best possible version of her powers; it's Final Destination, but in her favor. Domino's free-running over cars as they crash into the perfect position, fighting in rooms as toys conspire against her enemies, and requesting a bus, only to be handed one by the universe are all stellar action-comedy beats. She is dynamic to watch and there is so much more that can be done with her power. After all, being very good at fighting and extremely lucky is essentially the power Jackie Chan has in every film.
Domino walks into the movie partway through act 2 without a word of backstory, rules over a handful of action scenes, has a few fun comic dialogues, and sticks around at the end. As far as this universe is concerned, Domino just pops in wherever she feels fate pull her and winds up at an emotionally satisfying conclusion by the end. Truly any story could bend around Domino, she might carry the least baggage of any Marvel Comics character on the big screen. Backstory is a restraint, Domino is the perfect character to front the MCU's answer to something like Peacemaker. Fighting her way through the D-list mutants of Marvel's back catalog with her impossible powers could be an excellent early project for the MCU's mutants.
Domino is a perfect supporting character for Deadpool 2, but she's just too likable, entertaining, and well-presented to stay in that role. Zazie Beetz seems excited to come back, and the Deadpool films are a tremendous success. A spin-off would be a solid idea for the franchise, and Domino is the perfect character to carry that project. The Deadpool films will be carrying on, at least for one more ride, and it would be a shame to leave Domino in the past. Fans were lucky to have her, and making her a flagship character would be an immensely powerful move.