Espio the Chameleon is a purple anthropomorphic chameleon and an expert ninja. Espio's name is thought to either have been derived from the wor "espionage", meaning spying, or to be a reference to the Spanish and Portuguese word "espĂo" (Literally meaning "I spy").
Espio, unlike the majority of the Sonic characters, is very serious, calm, wise and disciplined, but also opinionated and somewhat arrogant at times. Despite this fact, he is usually eager to find danger to flex and polish his ninja skills. He is seen as a ninja-based character; his battle poses and shuriken stars support that portrayal. In the TV show Sonic X, when he was discovered by Amy while trying to sneak aboard the Blue Typhoon, he leaves in shame (before getting beaten up by being mistaken for Metarex). In Sonic Heroes, he plays the shamisen in the Chaotix' Team Blast, "Chaotix Recital". According to the Japanese Chaotix game manual, Espio especially dislikes Dr. Eggman, although it's not stated precisely why. During a cut-scene in Sonic Heroes, the usually civil and soft-spoken chameleon even threatened the doctor's life. He is also able to see through Eggman's tricks very easily in Shadow the Hedgehog, and tells Shadow to destroy the villain.