Ryan Joseph Hart, also known as Prodigal Son, Tsuujin, Robotnik, The Terminator and NeriahSensei, is a British professional fighting game player. He specialises in 2D and 3D fighter games released by Capcom, Bandai Namco, Sega, Midway, NetherRealm Studios and SNK. Ryan holds numerous National, European and World titles and has won the Evolution Championships twice in Tekken and placed in the top eight multiple times in the same series. Hart also holds four world records within the Guinness World Record's for most international Street Fighter competition wins, most well-travelled fighting game champion, the longest winning streak on Street Fighter IV, and the most consecutive opponents on Street Fighter V. While Hart is predominantly known for his professional gaming career, he is also a commentator, tournament organiser, author, presenter, event host, model, translator and content creator.

Hart was born and raised in South West London. At the age of 10 he visited his local arcade at a mini cab station, it was here that he was first introduced to his first arcade action game, Golden Axe. A year later he discovered the fighting games Street Fighter and Street Smart. When amusement arcades grew in popularity within the UK, Hart became a frequent visitor to the different arcades located around his local area, where he started to play Street Fighter and Street Fighter II: The World Warrior, among other games. For a portion of his teenage years, Hart was homeless. During his secondary school years, Hart's family relocated to Croydon in South London, where he frequently visited arcades and began to gain local reputation among classmates and arcade visitors.

Hart has worked in many different areas of the Esports industry, these include (but not limited to) professional player, tournament organiser, team manager, caster, interviewer, consultant, translator, model, coach and content creator.

Outside of Esports, Hart has also worked for many years in the video game industry, for companies such as Sammy Europe, Sega Europe and Nintendo of Europe.

Hart's first tournament was for the game Street Fighter II Turbo, held in London Trocadero in 1994, the event was sponsored by Kiss FM. It was also during this time he began to play King of Fighter '94, a year later Hart entered the National King of Fighter '95 Championship hosted by Play 2 Win arcade on Oxford Street, London. Unsuccessful in both tournaments Hart began to visit central London to play with more experienced players, it was there that he was introduced to Tekken and Tekken 2. It was with Tekken 2 that Hart had his first success, entering the Tekken 2 UK National Tournament, where he placed 4th with the character King.

With the release of The King of Fighters '96, Hart entered the National King of Fighters 96' Championship on 22 December 1996. This was the first competition that Hart won, defeating the player Motohide Nishio in the grand finals thus cementing his name among the King of Fighters community. Hart began to explore other fighting games, having huge success with Sega's Virtua Fighter 3, winning nine championships in a row at the Namco Wonderpark on 6, 7 and 8 June 1997, which was located on Great Windmill Street in Central London. With the release of Tekken 3, Hart trained heavily with his Tekken 2 background and went back and forth in arcades with other top players including Sho Hiraki from Japan, who was living in the UK at the time. Hart became the UK national champion defeating Sho Hiraki along his path in September 1997, and even appeared in a four player exhibition on the UK's GameMaster TV show again competing against the player Sho from Japan within the final, which he ultimately lost.

In 1998, Hart won the Ehrgeiz UK championship and a flight to Japan to compete in the Ehrgeiz World Finals, he was defeated but during his time in Japan, he entered and won the King of Fighters '98 World Tournament held at the Amusement Machine Show in Tokyo Big Sight. While still in Japan, Hart placed first in three Tekken 3 tournaments held at Shinjuku Playmax arcade. Adding to Hart's success within Japan, he also placed second at the Virtua Fighter 3 tournament held in Ikebukuro Gigo arcade. After returning to the UK, Hart entered the 1999 Official Namco Tekken 3 World Championship, it was there where he managed to win his second world title and one of the last Sony/Namco collaborated events within the Namco Station arcade.

After the closure of the Namco Wonderpark, Hart began to frequently visit Play 2 Win and Casino arcade within the city of London, shifting his focus from Tekken 3 and The King of Fighters, he started to play Tekken Tag Tournament and the newly released Virtua Fighter 4: Evolution. During the arcade decline within the UK, Hart began to organise tournaments within his own home, Casino arcade and London Trocadero, in an effort to support the competitive fighting game community and share knowledge. The success of these events lead to a weekly ranking battle held at the Casino arcade.^{[citation needed]}