Rex is one of the villains from the cartoon Max Adventures. He was one of the main antagonists in the season Max Begins, where he was a servant of the Shadow Master.
In the past Rex lived along his brother, the King Adisa the Lion Kingdom. Rex has always been very envious of his brother and conspired always knock him to become the new king. Some time after the birth of his nephew Max, Rex made an alliance with the dark lord Shadow Master for an invasion in the kingdom which ended in victory. Adisa was killed by Shadow Master, but Max was rescued and raised hiding in a forest for many years until his adulthood.
Max began a journey in search of the sacred Lion Crystals to defeat the Shadow Master. Rex after many years spent to wear a black hood to hide his face and continued to serve the Shadow Master. He helps the Shadow Master to win the crystals before Max, going to cheat at the end of the journey pretending to want to ally his nephew and then steal all his crystals.
At the end of the adventure when Max defeats Shadow Master and managed to regain the realm of the kingdom. Rex was arrested for betraying his own people.
- Rex is very similar to Scar from movie The Lion King, since both are lions, they were responsible for the death of his brother and uncles of the protagonists (Max and Simba).