Knuckles

Knuckles the Echidna, commonly known simply as Knuckles, is a sixteen-year-old red echidna from the  franchise and is the guardian of the Master Emerald on Angel Island. In the Mario & Sonic Olympics crossover installment series, he competes against Mario and others in Olympic style events in which he acts as a Power type character (meaning he excels at games that require brute strength, such as Hammer Throw or Javelin Throw). He is also the fastest of the Power characters. In Mario & Sonic at the Olympic Games, he was voiced by Dan Green, who also voiced Vector the Crocodile in that game. He was voiced by Travis Willingham from Sonic Free Riders up until Team Sonic Racing, where he is instead voiced by Dave Mitchell.

Mario & Sonic at the Olympic Games
Knuckles appears as a playable character in Mario & Sonic at the Olympic Games. He is a Power type character and does best at events that require strength.

Mario & Sonic at the Olympic Winter Games
Knuckles reappears in the game's sequel as a Power character again. In the DS version's story mode, Knuckles is found in Frostown, after Mario and Sonic defeats him in a mission, he'll join them and help them in their quest to free the snow spirits.

Mario & Sonic at the London 2012 Olympic Games
Knuckles returns as a Power-type character in the Wii version of Mario & Sonic at the London 2012 Olympic Games, where he appears in the opening with all of the other athletes and competing in Canoe Sprint 1000m and Football. A Mii outfit based on Knuckles can be unlocked, and he also appears as a character that can be spoken to in London Party mode in order to play minigames and earn stickers.

In the Nintendo 3DS version, Knuckles is included in the Wild Ones group, meaning that he is only playable in certain Events. In the Story Mode, Knuckles first appears with Vector chasing Bowser at Horse Guards Parade, and challenges him when Sonic shows up. When he and Vector win, Knuckles destroys the fog machine and clears the Phantasmal Fog form the area on Sonic's request, and then stays behind with Vector to interrogate Bowser, though it later turns out to be a hologram of him. Knuckles also calls Mario, Luigi, Sonic and Tails when they face Bowser and Dr. Eggman to support them and tell then that they've cleared the fog from Horse Guards Parade, and later appears at the opening ceremony. Knuckles also appears in the bonus episode The Life of a Minion, where he and Vector are tricked into competing in a match with Bowser, which they end up losing. A badge of Knuckles can also be obtained from the badge machine.

Mario & Sonic at the Sochi 2014 Olympic Winter Games
Knuckles is playable once again in Mario & Sonic at the Sochi 2014 Olympic Winter Games, and is yet again classified as a Power type character.

Mario & Sonic at the Rio 2016 Olympic Games
Knuckles returns once again in Mario & Sonic at the Rio 2016 Olympic Games. In the Nintendo 3DS version, he is exclusive to Javelin Throw and Boxing in the 3DS version.

Mario & Sonic at the Olympic Games Tokyo 2020
Knuckles reappears in Mario & Sonic at the Olympic Games Tokyo 2020 as a playable character. Like many other Mario and Sonic characters in the game, Knuckles wears outfits that are event-appropriate.

Super Smash Bros. Brawl
Knuckles also makes a cameo in the Green Hill Zone stage in Super Smash Bros. Brawl, running through the loop in the background along with Miles "Tails" Prower and Silver the Hedgehog. He also has a trophy in the game, as do many other characters from Sonic games. Knuckles does not make much of an impact on the game, however.

Super Smash Bros. for Nintendo 3DS / Wii U
Knuckles reprises his role from Super Smash Bros. Brawl in Super Smash Bros. for Nintendo 3DS, running in the background of Green Hill Zone, along with Tails and Silver the Hedgehog. A hat and outfit based off Knuckles appears as a wearable costume for Mii Brawlers in Super Smash Bros. for Nintendo 3DS / Wii U. Said hat was released on February 3rd, 2016, alongside other Mii Fighter hats, including a Tails hat.

Super Smash Bros. Ultimate
Knuckles appears in Super Smash Bros. Ultimate as an Assist Trophy. He attacks nearby players with Homing Attacks just like Sonic, and can also burrow underground and reappear at a different location, attacking with an uppercut. He also appears as a Spirit in Spirits mode. Knuckles reprises his role as a background character in Green Hill Zone. The Knuckles Mii Hat and Outfit from Super Smash Bros. for Nintendo 3DS and Wii U were released as DLC, on April 16th, 2019, to coincide with Joker's release.

Profile
"Knuckles is an echidna that shows exceptional versatility despite his overall strength in Power events. He'll perform best at events like throwing and rowing, but can also provide solid competition in many other competitions that aren't as power-based."

Profile
"Knuckles the Echidna has been friend and foe to Sonic for years. He has protected the Master Emerald on Angel Island, but now has his eye on a new prize: being #1 in the Olympic Winter Games! Powerful and determined, Knuckles will be going for gold with his Screw Driver ability on the Wii and DS, and Spiral Uppercut ability on the DS."