Collector

Location
The Collector is locked in the Tower of Love, which can only be accessed using the Love Key, found in the Queen's Gardens. The Tower can only be entered from the deep elevator shaft between Kingdom's Edge and the City of Tears. An exit to King's Station can be accessed after flipping a switch.

Behaviour and Tactics
The Collector erratically jumps around the room, avoiding attacks and occasionally trying to grab the player. The main threat in the battle comes from the glass jars it will drop down from the ceiling. They deal contact damage if they fall on the player and release enemies when they shatter on the floor. These include vengeflies, baldurs and aspids.

As the fight progresses, the Collector will get faster and more aggressive. Be careful with with healing, as the Collector is fast, and its movement pattern can be difficult to read. As always, Quick Focus can be quite helpful. Be wary of its grab attack, although it doesn't seem to use it too often.

Trivia

 * Defeating it rewards the Collector's Map, which will show the locations of Grubs that are not yet rescued on the map.
 * The Collector seems to be made from Void, similarly to Kingsmoulds who are also Void constructs. There is also a mould found in the White Palace within the King's laboratory that reveals "SERVE" when Dream Nailed.
 * If they player dies to the Collector, upon their return, they will find their Shade trapped in a glass jar.
 * The Collector is one of the few bosses to not give the player SOUL when hit
 * Striking the Collector with the Dream Nail will reveal that it has an obsession with preserving natural beauty.
 * Judging from the jars it uses, along with the three Grubs in its area and the map with Grub locations, The Collector is presumed to be responsible for all the imprisoned Grubs throughout Hallownest.
 * While the Hunter's Journal states it wanted to "preserve" the Grubs, it is unknown why it took a particular liking to them, nor why it left most of them in various locations while keeping all of its other "specimens" within the Tower of Love.