Not much about his past is known, or how he got into playing duel monsters.
Though Rex is vengeful, arrogant, and tyrannical, he plays fairly.
Rex's character design was overseen by Kazuki Takahashi. His usual outfit consists of a green jacket and a red beanie cap, plus tan pants. In duelist kingdom, he wears a tan vest-thing on his jacket, and a black shirt. In Battle City onward, he wears a green jacket, and a yellow shirt. His hair is brown with dyed purple strands next to his forehead. He has purple-blue eyes, whenever his irises are shown (his pupils are usually too small to determine his eye color). He carries a KaibaCorp Duel Disk on his left hand. In the Waking the Dragons arc he has a Chaos Duel Disk.
In the first Toei Animation movie, Ryuzaki has black hair with dyed pink strands and a purple cap.
Yu-Gi-Oh! Duelist Manga
Rex was invited to the Duelist Kingdom tournament. Due to his high ranking in the National Championship, he was given a luxury room for the boat ride, while other competitors had to sleep on the common room floor. On the boat, he was uninterested in Weevil's talk of there being new rules and said there was nothing more to the game than kill or be killed. He overheard Mai Valentine complaining about having to sleep on the common room floor and offered to let her sleep in his room. Mai took up his offer and pretended to flirt with him. While claiming she liked men stronger than her, she asked Rex if he wanted to Duel, offering to do whatever he wanted all night, if he won. Mai then began to put him off with her Aroma Tactics and asked if he still wanted to Duel, adding the condition that he would let her have the room to herself if she won. Rex accepted, but lost and was kicked out of the room.
On the the island, Rex won enough Duels to have five Star Chips. He then managed to find and confront Mai. He got mad at her for making a fool of him on the boat and demanded another Duel. Mai was not interested in playing someone that she already beat and told him to go away. As he boasted about having five Star Chips, Mai showed him that she had eight and said she had already decided who she would get her last two from, but needed to take down another guy before that. She then got the idea to get Rex to Duel Joey Wheeler and said he would Duel him if he won, thinking she could transitively beat Joey that way.
Rex was unhappy with doing her a favor, but agreed. Mai said that until they Dueled, Rex would be her slave. She also asked him if he knew what was "Something you can show, but can't see", but regretted asking when he answered that it was the octopus in a piece of takoyaki. Rex was taken to Joey, who accepted the Duel and wagered two Star Chips.
Rex stopped Joey using his "Time Wizard" and "Baby Dragon" combo, by destroying "Baby Dragon" with "Two-Headed King Rex" on his first turn and guessed that "Time Wizard" was Joey's face-down card. His Dinosaurs, powered by the Wasteland, overwhelmed Joey's monsters for the first few turns. Joey then used "Flame Swordsman", whose fire-based attack weakened Dinosaurs, to dispatch of some of Rex's monsters. Finally Rex Summoned, "Red-Eyes Black Dragon" and defeated "Flame Swordsman". He knew that "Time Wizard" was the only way Joey stood a chance of beating "Red-Eyes", but thought Joey would not know how to use it or be too afraid to try.
Rex then remembered that Joey defeated Mai with "Time Wizard" and thought that if he could get it himself, he would have no problem beating Mai. He imposed an ante, saying he would get "Time Wizard", if he won and Jonouchi would get "Red-Eyes Black Dragon" if he won. Mai objected and ordered Rex not to make the wager, but he refused to abide. However, the talk of "Time Wizard" reminded Joey that he had the card face-down and Rex's desperation to win it made him realize it was more powerful than he considered. Joey gambled and defeated Rex with the "Time Roulette" effect of "Time Wizard". Rex was later sent home, as he did not qualify for the semifinals.
Rex took part in the Battle City tournament and Dueled Esper Roba at an early stage. Roba had his younger brothers spy on Rex's hand and report what cards he had, through audio equipment. Roba pretended to get this knowledge via ESP. Rex lost the Duel, without doing any damage Roba's Life Points. In accordance to the ante rule, he lost his Puzzle Card and a rare card.
Rex warned Joey against Dueling Roba, stating that Roba could predict his opponents' strategies and thought that since Roba beat him, Joey did not stand a chance. However this encouraged Joey to challenge Roba, as he felt the first step to becoming a true Duelist was to not pass up on an opponent and the second step was to fight someone stronger than oneself. When Rex saw that Joey was gambling "Time Wizard", as his rarest card, he asked what happened to "Red-Eyes Black Dragon", still referring to it as his own card. Joey corrected him, claiming ownership of the card, but said that it got stolen, because he messed up. Rex was shocked, but Joey said he got the card back and his rival, referring to Yami Yugi, was holding it on to it for him. Rex and the other spectators laughed at Joey, for trying to Summon "Giltia the D. Knight", without Sacrifice, and thinking it got destroyed by ESP, when it did not work.
Yu-Gi-Oh! Duel Monsters (Anime)
Duelist Kingdom arc
Rex participates in the Japanese Duel Monsters tournament, where he loses to Weevil in the finals.
Rex was invited to the Duelist Kingdom tournament. Being a runner-up, in the last tournament, he was one of the few participants given a room on the boat journey. He invited Mai Valentine to his room. Mai challenged him to a Duel, where she would give him a kiss if he won (do anything he wants for him the Japanese Version), but she would get the room to herself if she wins.
Confident that he wouldn't lose, Rex accepts. However Mai insisted that they use her cards. Unbeknownst to Rex, Mai sprayed them with different perfumes and was able to tell what cards he drew. With this advantage, Mai won and booted Rex out of the room.
During the tournament, he was constantly berated by the fact Mai had Star Chips than him. He challenged her to a Duel to get revenge but Mai, preferring to avoid him, was content to use the excuse that she had already "beaten" him once. However since Mai had previously lost to Joey Wheeler and considered it obnoxious to challenge him again, she agreed to duel Rex, if he defeated Joey for her.
During his Duel with Joey, Rex gambled "Red-Eyes Black Dragon" in the hopes of winning Joey's "Time Wizard". (In the anime, "Red-Eyes Black Dragon" was an incredibly rare card that Rex received as a prize for being a runner-up in the last tournament.) This infuriated Mai as it would mean, Rex's Deck would be even stronger if she had to face him. However, Joey won the Duel and claimed Rex's "Red-Eyes".
Battle City arc
In the Battle City arc, he was seen briefly, losing to Espa Roba, who cheated and had "Jinzo" crush Rex's "Serpent Night Dragon". Rex then advised Joey on Roba's strength and left the tournament afterwards.
Battle City Finals arc
He later observed the semifinal match between Yugi and Kaiba in Domino City, amongst other duelists.
Waking of the Dragons arc
In the Waking the Dragons arc, it was revealed that he and Weevil lost a good deal of their popularity after the tournament and they eventually ended up wandering Domino City where they were ambushed by Gurimo. Their souls were taken, and later released when Yugi Muto defeated him.
The two of them then trailed after the party until Yugi's soul was taken by Rafael and they begged him to take them on their Helicopter. Rafael and Alister took them to Dartz, who agreed to give them power if they passed the necessary test. Each of them was given a piece of the Orichalcos Stone and both must succeed in grasping them, which both of them did.
Rex and Weevil improved their Decks by taking cards from Dartz's massive collection and Rex challenged Joey to a rematch. During the duel, Joey used Rex's "Red-Eyes Black Dragon" against him, much to Rex's displeasure and anger. Despite using "The Seal of Orichalcos" Rex lost at the hands of Joey's "Gearfried the Swordmaster," sending his soul to Dartz again. He was released at the end of the arc when Dartz was defeated. He and Weevil fled from the hospital they found themselves in. He then blamed Joey for this incident, and swear to make Joey pay.
Grand Championship arc
Their next plan was to enter the KaibaCorp's Grand Championship tournament, where they both impersonated Fortune Salim. They were quickly defeated by Zigfried von Schroeder and sent back to Japan by KaibaCorp.
Dawn of the Duel arc
Rex and Weevil's last attempt at revenge was to steal Yugi's Egyptian God Cards from his house, where they mistakenly grabbed Yugi's bag containing all of his Millennium Items. Yugi tried to stop them, but couldn't catch up. While examining their prize, they were then attacked by Yami Bakura, who stole the Millennium Ring back from them.
Ceremonial Battle arc
Rex is shown in the last episode of Yu-Gi-Oh! dueling with Weevil (not seen in the English version).
Yu-Gi-Oh! 5D's (Anime)
In Yu-Gi-Oh! 5D's, a parody of him named Dinosaur Hakozaki is listed as one the duelists defeated by Hunter Pace.
While at the Kaiba Land stadium, Rex is seen with Weevil as Kaiba gives a speech to the audience about Dueling, and his new Duel Disk.
Rex Raptor appears in the following video games:
- Yu-Gi-Oh! Capsule Monsters Coliseum
- Yu-Gi-Oh! Duel Links
- Japanese : Kin Fuji (Ep. 2 – 59), Yuichi Nakamura (Ep. 131 – 224)
- English : Sam Regal (Ep. 2 – 144), Anthony Salemo (Ep. 145 – 187), Christian J. Lee (Ep. 188 – 224)
all information on Rex Raptor came from http://yugioh.wikia.com/wiki/Rex_Raptor