Dark Fathom Armor
This dark, sea-soaked suit of armor smells of brine and is covered in eldritch runes. You have a +1 bonus to AC and can breathe normally underwater while wearing this armor.
In addition, while wearing this armor, you can use an action to cast the black tentacles spell (save DC 15) from it. When cast in this way, the spell targets a 15-foot square centered on your location that does not follow you when you move. In addition, you do not need to concentrate on the spell and are immune to its effects when cast in this way. Once this property has been used, it can’t be used again until the next dusk.
"The man became shrouded in an inky mist, coalescing into physical tentacles that whipped and writhed around him. No one dared to approach or follow him after that. Jakre still has night terrors in the barracks." —Excerpt from the diary of Guardsman Tren