Dark Roll is a movement command exclusive to Riku. It is equipped as a Dodge Roll-type command. It grants +2 to Defense and +20 to Dark Defense when attached to a Dream Eater recipe. can be tapped without a direction to Dark Roll if a Block-type command is not equipped, and Riku can control the distance dashed during Dark Roll; if the chosen direction is tapped or not tapped at all (if Block is not equipped), then Riku will Dark Roll a short slow distance forward. Holding a direction will increase the distance traveled.
Learning Dark Roll
Kingdom Hearts 3D: Dream Drop Distance