Sonic and the Black Knight is a Japanese manga written and illustrated by Hirono Makoto, and serialized by Dengeki Nintendo DS. It is based on the video game of the same name. It was released on 12 March 2009 which was the same day the game's release in Japan occurred.
In the beginning of the story, Merlina is being chased in the game by King Arthur. Arthur traps Merlina with a whole bunch of demons he summoned. Merlina, knowing she is trapped for good, summons Sonic from his world to save Merlina. Sonic, knowing how to defeat enemies, defeats the demons and counters King Arthur. He goes up to him, but Merlina pulls him back and transports Sonic and her away.
Later, in the Misty Lake, Merlina and Sonic find a sword on the stone. Sonic pulls the sword and it turns out to be Caliburn, a talking sword. Suddenly, King Arthur appears and Sonic goes up to King Arthur for a duel.