Question: What is the nationality of the UFC Heavyweight Champion who attended the Art of War 12 Fighting Championship ? 

full_context: Document 1: Ray Mercer: Raymond Anthony "Ray" Mercer (born April 4, 1961) is an American former professional boxer, kickboxer, and mixed martial artist. In boxing he competed from 1989 to 2008, and held the WBO heavyweight title from 1991 to 1992. As an amateur he won a gold medal in the heavyweight division at the 1988 Summer Olympics. As a mixed martial artist, Mercer is known for scoring an upset one-punch knockout victory over former UFC heavyweight champion Tim Sylvia in 2009.
Document 2: Frank Mir: Francisco Santos "Frank" Mir, III (born May 24, 1979) is an American mixed martial artist, who competes for Bellator MMA in the Heavyweight division. He formerly competed in the Ultimate Fighting Championship (UFC) for sixteen years. A former UFC Heavyweight Champion, he currently holds the record for most fights, victories, and submissions in UFC Heavyweight history, and is tied for 4th most UFC victories overall. Up until his release, Mir possessed the longest uninterrupted tenure of any fighter in UFC history. He is the first man to knock out and submit Antônio Rodrigo Nogueira.
Document 3: Tim Sylvia: Timothy Deane Sylvia (born March 5, 1976) is a retired American mixed martial arts (MMA) fighter, professional wrestler, and former two-time UFC Heavyweight Champion. He has competed as a Super Heavyweight and Heavyweight. While perhaps best known for competing in the UFC, Sylvia has also competed for Affliction, the International Fighting Championships (IFC), and ONE FC.
Document 4: Desert Force Championship: Desert Force Championship (DFC) is the largest mixed martial arts promotion company in the Arab World, which hosts most of the top-ranked Arab MMA fighters in the region. The championship has held ten televised events and presided over approximately 100 matches. DFC currently airs on MBC Action on a bi-monthly basis. In 2010 Desert Force launched the “Elimination Series”, a single-elimination tournament for Arab MMA fighters competing to become the first regional MMA title belt holders in 7 respective weight classes. Fighters from across the Middle East have competed in 7 weight classes, namely Bantamweights, Featherweights, Lightweights, Welterweights, Middleweights, Light-Heavyweights and Heavyweights; each class enforcing the Unified Rules of Mixed Martial Arts. Participating countries include: KSA, United Arab Emirates, Qatar, Kuwait, Jordan, Iraq, Bahrain, Palestine, Syria, Lebanon, Egypt, Morocco, Tunisia. In recent years DFC fights have been officially refereed by MMA referee Yves Lavigne.
Document 5: K-1 Grand Prix '99 Final Round: K-1 Grand Prix '99 Final Round was a martial arts event promoted by the K-1 organization. It was the seventh K-1 World Grand Prix final involving eight of the world's best fighters, with all bouts fought under K-1 Rules. The eight finalists had all qualified via elimination fights at the K-1 World Grand Prix '99 Opening Round. Also on the card was a number of 'Freshman Fights' and an 'Opening Fight' fought under a mixture of Jiu-Jitsu and K-1 Rules (various weight class) and two 'Super Fights' fought under K-1 Rules (various weight classes). In total there were twenty fighters at the event, representing eight countries.
Document 6: Ranik Ultimate Fighting Federation: Ranik Ultimate Fighting Federation (RUFF) is the first Chinese mixed martial arts (MMA) organization sanctioned by the General Administration of Sport of China. The winners of the title fights will be crowned as the national MMA champions of China in their respective weight classes. RUFF held its first event in August 2011 in Shanghai, before presenting in Chongqing, Hohhot, Nanjing, and Sanya. In February 2013 RUFF awarded Championship belts in five weight classes, at their Superfight event. Together with the Championship belt, each winner was awarded 1,000,000 RMB. RUFF along with Mandt Bros. Productions produced and aired a 10 episode reality series "RUFF: Journey" leading up to the Superfight. A new episode will air each week and will be nationally televised across China with TV viewership of over 30 million, over 10 episodes.
Document 7: Mark Coleman: Mark Daniel Coleman (born December 20, 1964) is a retired American mixed martial artist, professional wrestler, former NCAA collegiate wrestler and former Olympic amateur wrestler. Known as The Hammer, he was the UFC 10 and UFC 11 tournament champion, the first UFC Heavyweight Champion, and the Pride Fighting Championships 2000 Open Weight Grand Prix champion. At UFC 82 Coleman was inducted into the UFC Hall of Fame. At the age of retirement he was taking 150,000 USD salary per year.
Document 8: Art of War Fighting Championship: The Art of War Fighting Championship (英雄榜/Art of War/AOW) is a Chinese professional mixed martial arts promotion based in Beijing, China. The Chinese title "英雄榜" literally translated means "Gathering of Heroes." Art of War FC has no relation to the defunct US MMA promotion Art of War Undisputed Arena Fighting Championship. Art of War I was held at the Beijing Sports University on November 6, 2005. The inaugural event made it the first professional mixed martial arts contest in the People's Republic of China. To date, AOW has held 15 events in mainland China. Its largest event was Art of War 12 - Invincible, held at the National Olympic Sports Center Auditorium in Beijing on May 23, 2009 to an audience of around 6,000 fans. The event attracted many international guests, including former UFC Heavyweight Champion Tim Sylvia, renowned ring announcer Michael Buffer, and experienced referee "Big" John McCarthy.
Document 9: Ultimate Fighting Championship: The Ultimate Fighting Championship (UFC) is an American mixed martial arts organization based in Las Vegas, Nevada, that is owned and operated by parent company WME–IMG. It is the largest MMA promotion in the world and features the top-ranked fighters of the sport. Based in the United States, the UFC produces events worldwide that showcase eleven weight divisions and abide by the Unified Rules of Mixed Martial Arts. As of 2017, the UFC has held over 400 events. Dana White serves as the president of the UFC. He has held that position since 2001; while under the leadership of Dana White the UFC has grown into a globally popular multibillion-dollar enterprise.
Document 10: ONE Championship: ONE Championship (formerly known as ONE Fighting Championship or ONE FC) is a Singapore-based mixed martial arts (MMA) promotion which was launched on 14 July 2011 by multimillionaire entrepreneur Chatri Sityodtong and former ESPN Star Sports senior executive Victor Cui. According to CNBC, ONE Championship is Asia's largest sports media property with a global broadcast to over one billion homes in 128 countries.
Document 11: Antônio Silva (fighter): Antônio Carlos Silva (born September 14, 1979) is a Brazilian mixed martial artist who formerly competed in the heavyweight division of the UFC. He is a former EliteXC Heavyweight Champion, a former Cage Rage World Heavyweight Champion and a former Cage Warriors Super Heavyweight Champion. He has also competed for K-1 Hero's, BodogFIGHT, Strikeforce and World Victory Road. Known for being one of the five men (along with Tsuyoshi Kohsaka, Fabrício Werdum, Dan Henderson, and Matt Mitrione) to defeat Fedor Emelianenko in mixed martial arts competition.
Document 12: Super heavyweight (MMA): The super heavyweight division in mixed martial arts has no weight limit but generally refers to competitors weighing above 265 lb (120 kg). This is the definition used by the Nevada State Athletic Commission and the Association of Boxing Commissions.
Document 13: Women's mixed martial arts: While mixed martial arts is primarily a male dominated sport, it does have female athletes. Female competition in Japan includes promotions such as DEEP Jewels. Now defunct promotions that featured female fighters were Valkyrie, and Smackgirl. Professional mixed martial arts organizations in the United States that invite women to compete are industry leader Ultimate Fighting Championship, the all female Invicta Fighting Championships, Resurrection Fighting Alliance, Bellator Fighting Championships, and Legacy Fighting Championship. Now defunct promotions that featured female fighters were Strikeforce and EliteXC.
Document 14: Chuck Liddell: Charles David "Chuck" Liddell (born December 17, 1969) is an American retired mixed martial artist and former UFC Light Heavyweight Champion. He has an extensive striking background in American Kenpo, Koei-Kan Karate, and kickboxing, as well as a grappling background in collegiate wrestling and Brazilian jiu-jitsu. He had 23 fights in the UFC; along with Randy Couture, he is widely credited for bringing MMA into the mainstream of American sports and entertainment. On July 10, 2009, he was inducted into the UFC Hall of Fame.
Document 15: Randy Couture: Randall "Randy" Duane Couture ( ; born June 22, 1963) is an American actor, retired United States Army Sergeant, retired mixed martial artist and former collegiate and Greco-Roman wrestler. During his tenures in the Ultimate Fighting Championship (UFC), Couture became a three-time UFC Heavyweight Champion, two-time UFC Light Heavyweight Champion, an interim UFC Light Heavyweight Champion and the UFC 13 Heavyweight Tournament Winner. Couture is the first of only three fighters to hold two UFC championship titles in two different divisions (along with B.J. Penn and Conor McGregor).
ground_truth: American