All Cloaks are part of an armor set that boosts one skill by 2 points per level.
Each level your cloak acquires will increase the set skill by +2, and increase the rate of surging.
See Talk:Cloaks for the set ID that corresponds to a particular skill.
Because there are 35 different sets for Cloaks, each individual set/surge of Cloak is much less common than any given set/surge combination of Aetheria.
Cloaked in Skill (Increases all the targets skills by 20 for 20 seconds.)
Damage Reduction - "This cloak has a chance of reducing an incoming attack by 200 damage."
Your cloak reduced the damage from 162 down to 0!
Confirmed Drops
Lists of creatures and chests that are confirmed to drop specific level of cloaks. Click icons for individual lists - in progress - if you find cloaks on nonlisted creatures, please add it to the trophy section for that creature/chest):
The creatures at the locations associated with the different Societies wear cloaks with the emblem of their society: Creeping Blight, Celestial Hand, Eldrytch Web and Radiant Blood