Neoshadow

The Neoshadow is a Pureblood Heartless introduced in Kingdom Hearts Final Mix.

Kingdom Hearts Birth by Sleep
Back when Ventus was the apprentice of Master Xehanort, Xehanort called the boy to the Keyblade Graveyard and then summoned a swarm of Neoshadows for him to fight. Ventus was not strong enough to win with only his light, and although Xehanort ordered him to use the power of darkness to win, Ventus refused and was defeated. Xehanort instead decided to use his Keyblade to forcefully extract the darkness within Ventus's heart, creating Vanitas.

While Aqua is traversing the Realm of Darkness, she encounters the Neoshadow along with a few other Pureblood Heartless.

Kingdom Hearts 358/2 Days
After returning to the World That Never Was in order to reclaim Kingdom Hearts and revitalize Xion, Roxas is attacked by several Neoshadows. He eliminates them, but is forced to side with Riku in order to finish off the rest of the continuously spawning Heartless. As soon as the Heartless are taken care of, however, the two Keyblade wielders turn on each other.

Design
A Neoshadow has a more humanoid body structure than a normal Shadow, but shares the same pitch black skin and spherical, glowing yellow eyes. Its crooked antennae are quite long and fall back behind the Heartless. It seems to be rather muscular, and its hands are very large, each one sporting five clawed fingers. Its feet, like those of a normal Shadow, are long and lack digits, but a Neoshadow’s feet more resemble boots. Its body is also lined by several faint, blue veins of color.

The name “Neoshadow” is derived from the prefix “neo-“, which means “new”, and “shadow”.

Strategy
The Neoshadow is stronger and faster than a Shadow, and is more strategic in combat. In Kingdom Hearts Final Mix, the Neoshadows are among the most difficult common enemies, working together as a team to defeat Sora. In Kingdom Hearts: Chain of Memories, Kingdom Hearts 358/2 Days, and Kingdom Hearts II, they are less rare and dangerous but are still more difficult to defeat than regular Shadows. In Kingdom Hearts II, a powerful Reaction Command, Wind Dance, can be used to eliminate or intensely damage Neoshadows.