The following is an exerpt from a Legend Lore performed on Dragonborn Totems.
Watchers of the Morrasai Islands meant not originally to keep the Dragonborn safe, no. These are meant to mark the boundaries for the Dragons to keep them in check not to cross over into other territories so as to avoid all-out draconic war. These are one of the safety systems for Dragons to keep the peace. Brine gets privy to the fact all of these installed draconic totems are linked and controlled by Zargonoth the Ancient Green Dragon.