Cysts

Cysts are a Lost Sector-like activity type in the Pale Heart, introduced with The Final Shape. They are small trials sealed in secret areas.

Rotation

There are six Cyst missions, but only three appear on the map at a time. They pair up across three areas: The Landing (Searing Light / Slayer), The Blooming (Sword Dance / Moth-Infested Cavern) and The Impasse (Smothering Darkness / Aerial Ace). Interacting with the ghostly bird near an area's exit tunnel swaps the mission; you must leave and return before swapping again.

Unlocking

Cysts open up through the repeatable Alone in the Dark quest from Micah-10, which has six variants and includes finding a lost Ghost and playing Overthrow.