Heartless

A "Shadow" Heartless, the most common type of Heartless

Heartless (ハートレス, Hātoresu?) are hearts corrupted by darkness, lacking a body or soul, and commonly portrayed as having bright yellow eyes and dark colors. They serve as the most common type of enemy the player must face in the Kingdom Hearts games. Heartless come in a variety of types, categorized by being Pureblood or Emblem, both reproducing by taking more hearts and transforming them into Heartless. Pureblood Heartless are black shadow creatures born of pure darkness. Emblem Heartless were artificially created and are labeled with the Heartless insignia, a heart symbol with a thorny cross. The Heartless obey those with strong will.[16] However, in worlds closer to darkness, the Heartless get stronger and become uncontrollable. They invade worlds through corridors of darkness—unpredictable pathways that interlink the many worlds.