Knuckles the
Echidna is the last of the sworn
guardians of the powerful
Master Emerald in the
Sonic the Hedgehog universe. From his home on
Floating Island he patrols the land searching for trouble and keeps the fabled
emerald from falling into the wrong hands. He has quite an ego, but he is also easily duped. His special moves include the traditional
spin jump (although his jump is not as high as
Sonic's) and
spin dash plus he is able to glide through the air and latch onto walls, which he then climbs with great ease.
Knuckles' first appearance was in 1994's Sonic the Hedgehog 3, albeit in nonplayable form. The game opens as Sonic and Tails arrive on Floating Island where they are met by Knuckles who, having been tricked by Dr. Robotnik into believing Sonic has come to steal the Master Emerald, proceeds to distract and disturb the duo as much as possible. Over the course of the game he blows up bridges & platforms, turns off lights, and is a general nuisance.
Later in 1994 Sega and Sonic Team released Sonic and Knuckles which made the red echidna a playable character for the first time. Picking up where Sonic 3 left off, Knuckles pursues Sonic all across the island until they finally meet up in the Hidden Palace Zone (when playing as Sonic). They battle and Knuckles is defeated, but when he sees Dr. Robotnik stealing the Master Emerald he realizes who the true enemy is and joins forces with Sonic to open a path for the blue blur to pursue the Master Emerald. When playing as Knuckles our hero is simply transported to the final boss battle against Metal Sonic. Defeating him returns the Master Emerald to its resting place and the day is saved.
Of course, part of the charm of Sonic and Knuckles was the cartridge's ability to lock on to other Sonic games. Locking the cartridge on to Sonic the Hedgehog 2 unlocks Knuckles the Echidna in Sonic the Hedgehog 2, a special romp through the levels of Sonic 2 but featuring Knuckles. This quest did not occur in the official Sonic continity, however, and is considered just for fun. Locking the S&K game on to Sonic the Hedgehog 3 melds the two games together and allows players to take control of Knuckles throughout the entire combination of levels (of course the PC port The Sonic and Knuckles Collection and the Nintendo GameCube port Sonic Mega Collection includes these titles, so Knuckles also appears in them). He also returned for Sonic 3D Blast, but instead of being a playable character our hero simply stood around in various out-of-the-way places. If Sonic found him he could hand over any rings he had collected. When Knuckles was given more than fifty rings he'd send Sonic to the special stage.
Knuckles crossed over to the Sega Game Gear and appeared in both Sonic Chaos and Sonic the Hedgehog: Triple Trouble, however he had been tricked by Dr. Robotnik once again and believed that Sonic was the enemy. This plot was rehashed for the Neo Geo Pocket release Sonic the Hedgehog Pocket Adventure. Knuckles' only 8-bit playable appearance was on the Sega Master System's Sonic Blast. When the Sega 32X premiered Knuckles was given his first (and so far) only starring role in Knuckles Chaotix. Teaming up with a variety of Sonic has-beens and never-wases, Knuckles attempted to stop Dr. Robotnik from blowing up a new amusement park.
The Sega Saturn played host to Sonic R, a unique racing game, and Knuckles was one of the playable racers. Furthermore, this game saw the first and only appearance of Metal Knuckles, a robotic double of the echidna. As long as we're talking about racing let us not forget that Knuckles was one of the playable racers in Sonic Drift 2 for the Game Gear. Knuckles was also to be included in the ill-fated Sonic X-treme, but the game was sent to the trash heap before completion.
Knuckles showed up on the Dreamcast in both Sonic Adventure and Sonic Adventure 2 as a playable character in a 3D world. Sega's Mario Partyesque game Sonic Shuffle also featured the echidna in a playable role. When Sonic Adventure and SA2 were ported to the Nintendo GameCube as Sonic Adventure DX and Sonic Adventure 2 Battle, Knuckles went along for the ride. He's also playable in the Game Boy Advance's Sonic Advance and Sonic Advance 2, although in the latter he's a hidden character that must be unlocked before he's playable. His latest appearances occur in 2004's Sonic Heroes (where he's a part of a Team Sonic) and in Sonic Battle.
Knuckles has gone from nemesis to friend to Sonic mainstay. It's virtually guarenteed that he'll show in up future Sonic games in some capacity.