Vector

Vector the Crocodile, usually just called Vector, is the loud-mouthed leader of the Chaotix Detective Agency which he runs with his friends Espio the Chameleon and Charmy Bee. Never seen without his trademark headphones, Vector is always looking for jobs that pay, but would never refuse to help someone in need for free. Despite regularly getting into arguments due to his directness, Vector is a clever detective ready to solve any mystery. In the Sonic the Hedgehog series, he debuted in Knuckles' Chaotix and has become a recurring character ever since being brought back for Sonic Heroes. He is known for appearing in Mario & Sonic at the Olympic Games and its' subsequent sequels as a playable Power type character, but has also made minor appearances in the Super Smash Bros. series. In the Mario & Sonic series, he acts as a rival to both Bowser and Donkey Kong.

Mario & Sonic at the Olympic Games
Vector appears in the first game of the series, Mario & Sonic at the Olympic Games. He is a Power type character, and can take on any event that requires strength.

Mario & Sonic at the Olympic Winter Games
In the Adventure Tours mode in the Nintendo DS version, Vector the Crocodile is first mentioned by Charmy Bee when Mario, Sonic the Hedgehog, and Toad run into him when the bee refused to let the trio get pass him. Toad then tells Charmy they will let him know when they see Vector.

Later in Icepeak, Vector is seen next to a mission sign and he knows Mario and doesn't know that if Sonic is with him. He tells the trio he will join the group if Donkey Kong defeats the music-loving crocodile in a match of Short Track 500m. Once Donkey Kong defeats Vector, he then joins the party.

Toad then tells Vector that Charmy needs to see him back in Cubyrinth. When they arrive in Cubyrinth, Charmy tells Vector in order to open the gate, he must engage in a quiz based on Real and Dream Winter Olympic sports and the islands of the snow spirits. He tells him if he gets 5 questions correct within 45 seconds, he will open the gate and let them through. Vector succeeds, and they go through.

Espio is seen when he tells his friend to let him know how many more whitestones are there in Sparkleton, Cubyrinth, and Blizland. When all the whitestones are found in those islands, he gets surprised that there's none left when the player collects all of them.

Mario & Sonic at the London 2012 Olympic Games
In the story mode in the Nintendo 3DS version of the game, Sonic arrives at the Volleyball court and is almost killed by Bowser as he surprise attacks. Knuckles the Echidna and Vector the Crocodile helps out and challenges him to an event and lets Sonic go. They defeat him and he runs away to escape before Sonic crushes his machine. The Wild Ones destroy the machine and Sonic and Tails move on.

Mario & Sonic at the Sochi 2014 Olympic Winter Games
Vector appears again in Mario & Sonic at the Sochi 2014 Olympic Winter Games. He returns as a Power type character.

Mario & Sonic at the Rio 2016 Olympic Games
Vector appears again in Mario & Sonic at the Rio 2016 Olympic Games. He returns as a Power type character.

Profile
''Rough-and-tumble Vector is a crocodile that loves money, which means he wants that Gold Medal more than anything. With incredible Power skills, he'll perform well in the throwing events and, given his unique swimming stroke, can excel in the pool as well.''

Profile
''Vector the Crocodile is large and strong, and heads the Chaotix Detective Agency. Vector's Head Slide abitily on the Wii and DS, and Gum Balloon ability on the DS will put him toe-toe with the other contestants as he goes for #1!''

Profile
With a love of all things gold, this crafty croc will use his impressive strength to snag as many Gold Medals as possible.

Trivia

 * Coincidentally, Vector bears a resemblance to the Kremling species.
 * Vector, along with Charmy Bee, has only appeared in three games before the Mario & Sonic games: Knuckles' Chaotix, Sonic Heroes, and Shadow the Hedgehog.