Knight

The Knight is a special type of enemy that can only be damaged from the brain in the back of their heads. However, explosions or attacks that pierce enemies, such as, or melee attacks i.e , ,  and , will allow damage to be applied from any direction. The Knight normally walks around in random directions, but once the player is directly in front of it, it will dash towards the player at a slightly faster speed until it hits a wall.

Selfless Knight
The Selfless Knight has a similar appearance to an ordinary knight but has an Isaac face on its back instead of a brain. This version is much faster than the normal version, especially while charging.

Floating Knight
The Floating Knight is similar to the ordinary Knight but can fly over all obstacles. It also moves slightly slower.

Bone Knight
The Bone Knight is similar to the ordinary Knight but leaves behind a short-lasting trail of damaging Red Creep, making it much harder to attack its vulnerable side. Its charge is faster than an ordinary Knight, but not as fast as the Selfless Knight.

Loose Knight
The Loose Knight is similar to the ordinary Knight, but moves slower and separates into a Brainless Knight and Pon when its health is depleted.

Brainless Knight
The Brainless Knight is a variant of Knight created when a Loose Knight takes enough damage. It alternates between running around the room along the cardinal directions and aimlessly walking in circles, charging at Isaac when he gets in line of sight. It dies when its corresponding Pon dies.

Black Knight
The Black Knight is a variant of Knight that has slightly higher health and will slowly move towards Isaac's position at varying speeds. After lining up with Isaac it accelerates forward, sending waves of fire in the cardinal directions and becoming stunned momentarily after colliding with a wall or obstacle. A Black Knight's mask will also reflect any of Isaac's tears that come in contact with it. It is almost entirely immune to knockback and other forces that would displace it (such as ).

Trivia

 * In Antibirth, Brainless Knights were referred to as Empty Knights.
 * Black Knights had a slightly different appearance in Antibirth and would spawn in the Mausoleum.