As was already posted long time ago by Exit, Pursued by A Sloth, Marnie was summoning Frucissiere (we see his sigil around Minerva) But according to Blue ray’s she was also summoning another demon: Berith.
In S4E1 Marnie: “ Restore within her the spirit of life. Evocare lemures de mortuis, and return her to the plane of the living. Hic en spiritus, sed non incorpore, evocare lemures de mortuis, decretum expugnare de angelus barbarus en inferno erem irbanes." Now according to BR’s she is actually saying “here in spirit but not in body, I call up the ghosts of the dead – by force of decree, from the angel Balberith from Hell inescapable.”
Berith (Balberith, Baalberith, Beal, Belfry, Bofi , Bolfri, Elberith) FALLEN ANGEL. Berith appears as a man wearing a soldier’s uniform and a golden crown and riding a red horse. As an angel, Berith was prince of the order of cherubim. As a DEMON, he serves as a master of ceremonies, duke, and grand pontiff in HELL, residing over 26 LEGIONs of demons. He notarizes PACTs with the DEVIL. Berith was important to some alchemists, who believed he had the power to transmute all base metals into gold. He was tricky to conjure, however, and had to be summoned with magic rings bearing his SEAL. He was known for making great promises, but also for being a great liar. Berith will appear and do as commanded—but he will claim his reward, the conjuror’s soul, in 20 years’ time. He is also said to foretell the future.
Baalberith is Hell’s Minister of Treaties. His name appears at the bottom of a document produced in the seventeenth-century trial of Urbain Grandier. The document, of dubious origin, is supposedly a pact signed by Grandier with Satan and a number of other high-profile devils in witness. Grandier was accused of witchcraft and diabolism in Loudun, France, and this little document was one of the things that sent him to the stake. Baalberith appears as "scriptor," and as far as this document is concerned, he seems to function in the role of scribe or secretary for Satan's pacts. Interestingly, Baalberith's name may clearly define this particular job description. Baal meant “lord" in several ancient Semitic languages, and was typically used as a title of an order of Canaanite gods, all duly objected to by the monotheistic Israelites and generally decried as demons. Berith is Hebrew for "covenant." It refers to the sacred covenants established between the Lord God and his chosen people, and it is used as one of the names of God. Here, perverted into the name of a demon, it seems to suggest that Baalberith is the “Lord of Covenants," which, in demonic lingo, would make him the Lord of Pacts. Notably, Berith appears as a demon in the Goetia and elsewhere in the grimoiric literature.
Famous pacts with demons/devil are signed in blood and often in exchange for something, the usual locations are crossroads and bridges. Could Marnie summoning Berith have something to do with Warlow being awakened/appearing to the scene ?
http://www.jewishencyclopedia.com/articles/2236-ba-al-and-ba-al-worship
http://www.jewishencyclopedia.com/articles/2238-baal-berith
http://en.wikipedia.org/wiki/Deal_with_the_Devil
http://frogstorm.com/?p=4420
http://en.wikipedia.org/wiki/File:Haitzmann_pakt.jpg