After 18 years and more than 120 fights, “The Beast” is hanging up his gloves. Dan Severn announced Monday that he has retired from active competition in mixed martial arts, the sport he helped pioneer in the early days of the Ultimate Fighting Championship In a post on his official website titled “Another Chapter Comes to a Close,” the 54-year-old Michigan native stated that his goal for 2012 was to conclude the fighting portion of his career.“I was attempting to do my own self-directed retirement tour in the last couple of years, reaching out to only three people,” wrote Severn, who said he had pursued rematches with fellow UFC Hall of Famers Royce Gracie Ken Shamrock and Mark Coleman . “It seems as though these matches will not take place for whatever reasons and my life now goes on to the next chapter.”Despite his most desired fights not coming to fruition, Severn stayed busy in the past two years, competing in 11 bouts throughout North America while also taking part in pro-wrestling matches and instructional seminars.“It has been difficult to juggle so many different parts of my career, but that is when opportunity presented itself... such as my MMA career beginning at the age of 37, and now ending at age 54. Father Time is telling me, it is time to let go,” Severn said. “I have learned over time that the only constant factor is change. It will happen, and there is nothing we can do to stop it, so smile, hold on, and embrace it for all that it has to offer, and hopefully you too will have the ride of your life!”Severn will continue to perform in pro-wrestling through the end of 2013, and also plans to remain active in MMA as a teacher, commentator and ambassador. He also wrote that he intends to increase hours at his Michigan Sports Camps training facility in Coldwater, Mich., along with penning a biography and doing more public speaking engagements.A former NCAA All-American wrestler at Arizona State, Severn transitioned to MMA in 1994 when he debuted at UFC 4. While his run in that one-night tournament ended in a submission loss to Gracie, Severn would capture the tournament crown in his next attempt at UFC 5. Despite last competing in the Octagon at UFC 27, he was inducted into the UFC Hall of Fame during UFC 52 in April 2005. Severn leaves the sport with an impressive career record of 101-19-7, including 60 wins via submission.