Espio the Chameleon (エスピオ・ザ・カメレオン, Esupio za Kamereon?) is a purple anthropomorphic chameleon and an expert ninja. Espio's name is thought to either have been derived from the word "espionage", meaning spying, or to be a reference to the Spanish word "espio" (Literally meaning "I spy").
Espio, unlike the majority of the Sonic characters, is very serious, calm, wise and disciplined. 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 a 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.
Espio, being a chameleon, can render his skin to match the environment, which makes him completely invisible, unless he gets something on him, such as paint, that allows him to be seen (and he did get paint smeared on himself in Sonic X episode 59). He is quite skillful with shuriken, and is said to own the biggest collection of them known to man. Some of his shuriken are also modified to explode within a certain time once they make contact to a target, like small time bombs (also seen in Sonic X episode 59). He also can run quite fast, as he is the Chaotix speed member in Sonic Heroes. He can also perform the homing attack like the other speed members, and can create small tornadoes (known as "Leaf Swirl") while turning invisible. Due to being a chameleon, he can also stick to and walk on walls and ceilings, and can quickly extend his long tongue in order to damage enemies. He can perform the Spin Attack and Spin Jump, along with his own variations of them, the Whirl Attack and Whirl Dash (appeared in old games; he uses the spin versions in Sonic Heroes and Shadow the Hedgehog). Espio can also charge forward destroying all enemies in his way, and, as mentioned above, throw over-sized shuriken, as well as kunai. Once, he was even seen with a ninja sword. In the Archie series, Espio has been shown using his tongue as a grapnel. In Sonic Heroes it was revealed that Espio could play the shamisen, through their Team Blast: Chaotix Recital
- Espio is the only member of Team Chaotix to appear in a game released between Knuckles' Chaotix and Sonic Heroes.
- In Knuckles' Chaotix and Sonic the Fighters, Espio has different shoes than his current design. As in the past games, his shoes were green, and they are currently purple.
- Espio has an equal amount of playable appearances and one less overall appearances than Vector (due to Sonic Chronicles), making him the second-most used Chaotix member. Charmy has been playable in three less games than the both of them.
- In Sonic Heroes, Espio is the only Speed-type character who is not a Hedgehog.
- Through the games Espio's color gradually lightens from a dark purple to a light pink-ish purple.
- Strangely, in the older comics, he is shown as a sky blue color, but is changed later for consistency with his game appearances. Though, he may posses the ability to change colors since normal chameleons can.
- In Sonic Heroes, Espio is the only speed formation character whose shoes do not involve the color red.
- Espio's spines seem to change colors from game appearances. In Knuckles' Chaotix and Sonic the Fighters, they were green. In most appearances, they were black and in Shadow the Hedgehog, they were pink.
- In the Shadow the Hedgehog level, Egg Breaker, when Shadow destroys any of Eggman's robots, Espio says, "Stop that! We can't let Eggman know we're here!" which is repeated from the previous level. However, Eggman already knows that Espio and Shadow were in his base as he is fighting them.
- It is unknown where Espio got his skills as a hacker.
- In Sonic Heroes, Espio is one of the most violent characters (behind Omega), as he frequently says death threats, particularly to Eggman.
- In Shadow the Hedgehog, Espio is one of the 5 characters to curse (the others being Shadow, Sonic, Knuckles, and the GUN Commander).
- Espio is the only character in Sonic Rivals 2 to not appear in Sonic Rivals.
- In Sonic Generations, Espio is the one of the two characters who didn't notice Sonic was different after being rescued. The other was Vector.
- It has been noticed by some that Espio has an almost identical quill structure to Metal Sonic. This is most apparent in Sonic Heroes.
- Espio is capable of turning invisible by using his chameleons abilities. This shows that he can also change the colour of his eye balls, shoes and gloves. This also means that it could be possible his real scale and eye colours aren't purple and yellow, and that he is just constantly changing their colours.
- He is the only animal character in Knuckles Chaotix to have been created originally for that game, as Vector, Mighty, Charmy, and Knuckles had all appeared (or in Vector's case, was going to appear) in a previous game. Knuckles (Sonic 3), Mighty (SegaSonic), Vector (Sonic 1), Charmy Bee (Sonic manga).