Dark Mind is a mysterious figure who wanted to conquer the Mirror World, so he corrupted it with his evil. Meta Knight found that this would threaten Dream Land, so he went to the Mirror World. However, he found himself beaten and imprisoned by his evil counterpart, Dark Meta Knight. It was then up to Kirby and his newly-born clones to save Dream Land and the Mirror World, so they ended up there.
Powers and Stats
Tier: At least 4-A
Name: Dark Mind
Gender: Vaguely male
Classification: Dark Entity
Powers and Abilities: Superhuman Physical Characteristics, Dimensional Travel, Flight, Teleportation, Regeneration, Elemental Manipulation, Energy Manipulation, Can create mirrors and manipulate them to redirect attacks or summon enemies, Reality Warping (Corrupted the mirrors of the Mirror World, which were able to grant wishes), He's capable of flipping the entire setting upside down (although this attack's range is unknown).
Speed: Massively FTL+ (Comparable to Kirby and was capable of keeping up with his Warp Star)
Lifting Strength: Unknown
Striking Strength: Unknown
Durability: At least Multi-Solar System level
Range: Standard melee range. Multi-Universal with reality warping (Used the dark side of everyone's hearts in the real universe to create evil versions of them, corrupting the inhabitants of the Mirror World.)
Weaknesses: None notable