The Shadow is a Pureblood Heartless that is found throughout the Kingdom Hearts series. Although some Heartless (such as the Creepworm) are weaker than the Shadow, it is the most basic type, and is still a threat to those without the Keyblade.
It is found in each world in every game, excluding Kingdom Hearts Birth by Sleep, Atlantica in Kingdom Hearts, Kingdom Hearts: Chain of Memories, Kingdom Hearts II, and The World That Never Was in Kingdom Hearts 358/2 Days. Meanwhile, in Kingdom Hearts Birth by Sleep Final Mix, this Heartless appeared only in the Realm of Darkness during the Secret Episode of the game.
A normal Shadow has a vaguely humanoid body structure. It has a round, spherical head with circular, glowing yellow eyes. It also has two long, twisted antennae sprouting out of the top of its head. Each of its hands has three clawed fingers, and its feet are large and lack any discernible digits. With the exception of its eyes, this Heartless's body is completely black (with the exception of the Shadows summoned by the Dark Follower, which are dark purple).
The Shadow's name is a reference to a shadow, highlighting its status as the most basic type of Heartless. The name could also be a reference to the Shadow's ability to flatten itself into a silhouette on the ground, and become a literal shadow.
Shadows live up to their name, emerging from the ground to attack with a simple but fierce claw strike. Although the Shadow is relatively easy to defeat when alone, its habit of attacking in swarms can make it too much to handle. If it is too much, it is a good idea to use Thunder (only in Kingdom Hearts) because it has a wide range. If it is alone, just whack it with the Keyblade.