SONIC AND THE SECRET RINGS

NA Release: Feb 20, 2007
EU Release: Mar 3, 2007
JP Release: Mar 15, 2007

All information below was provided by Ekajra. Thanks! :)

Knuckles cameos as the Arabian Knights character Sinbad of the Seven Seas. Sonic and Shahra first run into him after Ali-Baba (Tails) tells them where he is because they need his Blue World Ring that can control weather to defeat the Ifrit (big fire golem), who is the boss of Evil Foundry. You find him after the first mission in Levitated Ruin locked in a cage, which in the next mission you must unlock to get him out so he'll help. After he is let out, there's a brief fight between him and Sonic (which Ali-Baba coincidentally breaks up), and then he tells them of how pirates captured him and stole the ring, which leads into the next level, Pirate Storm.

Knuckles is also playable in the multiplayer party mode.