Every year, one narrative seems to step up and dominate the UFC year.In 2011, the incredible rise of Jon Jones was clearly the “Story of the Year” in the UFC, as the prodigious light heavyweight talent earned four victories in the span of ten months, rising to the top of the division with his win over Mauricio “Shogun” Rua in March before defending the title twice over the final four months of the year.Last year, rather than a fighter stepping out as the biggest story, the rash of injuries that tore through the roster, producing innumerable lineup changes and the first event cancellation in UFC history was the most discussed narrative.Though we‘re just three months into the year, the success of former Strikeforce fighters inside the Octagon is already emerging as a clear early favorite to be the dominant talking point of 2013.FIRST QUARTER IMPACT PERFORMERSAny discussion of the impact arrivals from Strikeforce has to start with the UFC women‘s bantamweight champion Ronda Rousey. The former Olympic bronze medalist is a promotional force of nature, and equally as impactful inside the cage as well.The build-up to her UFC debut was covered more extensively than any fight in recent memory, and her headlining turn with Liz Carmouche atop the UFC 157 Pay-Per-View was a complete success. In addition to retaining her title with another first round armbar victory, Rousey established herself as a legitimate headlining act in the UFC, and a certified star in the sport.The spotlight isn‘t going to wane any time soon either, as “Rowdy” will get her wish to serve as a coach on The Ultimate Fighter next season, leading a mixed cast of bantamweights opposite the winner of the upcoming Miesha Tate-Cat Zingano fight in April on FX.While the women‘s bantamweight champ has made the biggest splash of any crossover competitor so far this year, the unbeaten Rousey isn‘t alone on the list of former Strikeforce fighters to have already delivered big things inside the Octagon in 2013.Last Saturday night in Montreal, young Canadian welterweight Jordan Mein added his name to the growing list of UFC first-timers to make an impression in the opening months of this year. The 23-year-old Lethbridge, Alberta native announced himself as someone to watch in the welterweight division by escaping an early armbar to become the first man to stop veteran Dan Miller.After more than seven years away from the Octagon, Robbie Lawler made a successful return to the UFC last month, earning a first round knockout win over Josh Koscheck at UFC 157 in Anaheim. That same night, Nah-Shon Burrell and Yuri Villefort opened up the show with a wildly entertaining back-and-forth battle, displaying a tremendous sense of urgency from the opening bell to the final horn.UFC 156 produced three wins for former Strikeforce competitors.The last man to beat Mein, Tyron Woodley, also made a splash in his UFC debut in the opening stages of the year, knocking out Jay Hieron in just 36 seconds. With the win, “The Chosen One” inserted himself in the thick of the chase in the welterweight division, and the former University of Missouri wrestling standout will be looking to take another step up the rankings this summer when he takes on another Strikeforce alumnus, Jake Shields, at UFC 161 in Winnipeg, Manitoba.Lightweight veteran and Team Jackson-Winkeljohn product Isaac Vallie-Flagg outworked Yves Edwards to push his unbeaten streak to 12 and collect his first UFC victory, while Bobby Green captured Dana White‘s attention with his third round submission win over Jacob Volkmann. White could not stop praising Green after the event, lauding his ability to overcome a questionable referee‘s stand up and his drive to finish Volkmann in the third to ensure he earned the win.MORE NAMES TO WATCH ON THE WAYWhile there is no question that several fighters that have migrated to the UFC since the collapse of Strikeforce have already impressed, there are even more talented athletes who have yet to make their first appearance in the Octagon who could easily add their names to the list of impact arrivals from the closed down company in the coming months.Gegard Mousasi makes his debut early next month in a headlining turn opposite Alexander Gustafsson in his hometown of Sweden. The former Strikeforce light heavyweight champion has the chance to halt the surging Swede‘s climb towards a title shot, and inject himself into the conversation at the same time with a victory.Once considered a can‘t miss prospect, injuries have hindered Mousasi in recent years; he missed all of 2012 after suffering a torn ACL, and dealt with various maladies in the year before that as well. He‘s still only 27 years old, however, and already has a great deal of experience under his belt, so it‘s quite possible that he could return to make an immediate impression in the 205-pound ranks.In the co-main event of next month‘s FUEL TV fight card in Sweden, second-generation UFC competit…