Mehrien, of Jaguar Black, is a member of the Sentinels of Nature and a Siren, though unlike other members of her race, she is not at all soft nor feminine. As her title suggests, she belonged to the since-disbanded ancient sect of protectors and warriors within the House that boasted the mightiest sentinels as its members, including Covenant Stormcrow. Wearing the chainmail reserved for members of Jaguar Black, Mehrien observes her surroundings vigilantly, sporting a tattoo of the mighty jaguar upon her shaved head. She wields a trident in her right hand, while her raven companion perches upon her left, murmuring to its mistress in a gutteral voice.
A member of the Sentinels of Nature since its days as a Guild, Mehrien partook in the follow-up expedition of Ulangi led by Oswald Snowmantle shortly after his discovery of the island. It was here that she, along with Onakk and Antion, was kidnapped by a triton raiding party. For countless years, the three were held captive and forced to work within the silver mines of Scyros, until Lupar of 467 AF, when for unknown reasons, they were released and left stranded upon the island of Tuar. During this time, Vixen, the House tutor, began experiencing vivid dreams of them and the island; following clues revealed in her visions, the Sentinels of Nature, in a joint effort with members of the Divine Order of Neraeos, succeeded in finding the island of Tuar and rescuing the three sentinels, bringing them back to the House estate in Eleusis.