A Gatekeeper is a winged creature with unique magickal abilities. Gatekeepers can be difficult to defeat since they summon other creatures frequently and can shield themselves from damage with their wings. It is easy to tell when entering a room haunted by a Gatekeeper: the floor will be shrouded in a thick mist of the appropriate colour.
In all cases, the Gatekeeper attacks in the same way. It moves slowly towards the character; when within striking distance, it will rear up, spreading its wings. Then it will stab the character with its scythe-like tail, dealing a small amount of damage and paralysing them for a short time. It will immediately use this time to summon a creature. While Gatekeepers will typically summon zombies or trappers, the two Gatekeepers in the Forbidden City's amulet room during Michael's chapter will summon Horrors. Like with players and summoning spells, a Gatekeeper's summoned creature will die instantly if it summons a new creature. Unlike with Guardians, a Gatekeeper's summoned creatures will survive and continue fighting if the Gatekeeper is killed.
If a player is using a shield spell when hit by a Gatekeeper, the Gatekeeper will dispel the entire shield regardless of what strength it is.
In all cases, wait for the creature to rear up, spreading it's wings, and then use your ranged weapon of choice to shoot it in the head. Immediately turn and run after this, to avoid it's attack. Alternatively, it's possible to run around the Gatekeeper and attack its back, which is vulnerable while its wings are shielding its front. If the Gatekeeper closes its wings after taking Mantorok-aligned damage, it will immediately cancel out the damage over time effect.