TV-Series
Description
Rex Owen, originally Rex Ancient, serves as a core protagonist in the *Dinosaur King* narrative. Born during the Mesozoic Era to paleontologists Dr. Ancient and Dr. Cretacia aboard the time-traveling Backlander, his infancy saw conflict with Dr. Z, who exploited dinosaurs for entertainment. An attack by Dr. Z and Seth sent Rex forward in time while displacing his parents. Discovered as an infant within an egg-like container at the Smithsonian Museum by paleontologist Dr. Owen, he was adopted. Due to Dr. Owen's frequent fossil-hunting expeditions, Rex lived with Dr. Spike Taylor's family, forming a close bond with Max Taylor.

Characterized as quiet, intelligent, and cautious, Rex often displayed a serious demeanor contrasting with Max's impulsiveness, leading to occasional conflicts. Despite this, he possessed a fundamentally good heart and demonstrated strong loyalty to his friends. He exhibited a short temper when cherished possessions like his trilobite fossil or dinosaur book were damaged and harbored a crush on fellow D-Team member Zoe Drake. His cautious approach sometimes complicated adventures, but he consistently prioritized aiding endangered friends, setting aside personal disagreements.

His journey with the D-Team began when he, Max, and Zoe discovered three elemental stones and dinosaur cards after a meteor impact. Rex bonded with the Wind Stone, activating the Carnotaurus card and naming the dinosaur Ace. Ace became Rex's constant companion; in his smaller "chibi" form, Ace displayed playful behavior that occasionally annoyed Rex, though Rex deeply valued their partnership. In battle, Ace utilized wind-based attacks, relying on speed and agility as the fastest member of the D-Team's dinosaurs. Ace exhibited a fear of large bodies of water.

Rex's background formed a central plotline. Initially unaware of his origins, he learned the truth through Jonathan: his parents were time travelers from 2126 AD. He later reunited with Dr. Ancient and Dr. Cretacia. During the conflict against the Spectral Space Pirates, Rex, his parents, the D-Team, and the reformed Alpha Gang joined forces. They pursued Cosmos Stones across time to rescue kidnapped parents and thwart the pirates. Following the pirates' defeat, Rex, his parents, Jonathan, and the Alpha Gang used the pirates' damaged spaceship for a single trip back to 2126, meaning Rex could never return to reunite with Max and Zoe.

Outside the main anime, Rex appeared in other media. The manga depicted him as an American transfer student initially isolated by language barriers. His friendship with Max blossomed after Max noticed his interest in dinosaurs. Together, they discovered a fossil that broke, leading Rex to wear the larger fragment as a necklace. In this version, his dinosaur partner was a carnivore named Benjamin, found by Max at Alpha Mountain. Within the Nintendo DS game, players could select Rex as the protagonist, starting with a Carnotaurus, though the core storyline remained consistent regardless of choice.

Physically, Rex had pale skin, blonde hair featuring distinctive ahoge strands, and blue eyes. He typically wore a blue jacket over a white t-shirt, brown pants, and blue sneakers. A prominent dinosaur tooth necklace, larger than those worn by Max and Zoe, served as a signature accessory. The name "Rex Owen" combined "Rex" (derived from Tyrannosaurus rex, meaning "king") and "Owen" (likely referencing Sir Richard Owen, the scientist who coined the term "Dinosauria").