Note: Pulling one type of mob will cause the rest of the mobs of that type to link, regardless of where they are in the chamber. When pulled, it appears that everyone in the room gains hate, regardless of whether or not they have acted on the mobs.
The enemies come in three waves, with the first and second wave each featuring 1 type of the below enemies (excluding enemies spawned from bosses), and the third wave featuring 1-2 types of the below enemies plus a boss.
Huginn, Muninn, Heithrun or Saehrimnir will not be immediately seen. They will pop as you progress through the chamber's monsters. Muninn and Saehrimnir will leave behind a message stating "the chamber's stagnant aura has somewhat cleared" if defeated or left to depop respectively.
Huginn will leave behind an Armoury Crate containing various consumable items upon defeat.
Muninn will weaken the enemies upon defeat. A message stating "the creatures lurking in the shadows have calmed" will be received.
It is currently unknown what Heithrun does. It is, however, reported to be the rarest of the four.
Saehrimnir will strengthen the enemies if left to despawn. A message stating "the creatures lurking in the shadows have become restless" will be received.