Mater Tenebrarum, or the Mother of Darkness, is one of the Three Mothers; the other two are Mater Suspiriorum, the Mother of Sighs, and Mater Lachrymarum, the Mother of Tears. Together, they are powerful witches who rule the world with "sorrow, tears, and darkness". The youngest and most cruel of the Three Mothers, Mater Tenebrarum's true name is not revealed. She resides within New York, in a building that was christened in 1910 and bears a plaque that claims George Ivanovich Gurdjieff was there. In Inferno (1980), Mater Tenebrarum was portrayed by Veronica Lazar.
Like Mater Suspiriorum, the Mother of Sighs, whose presence was foretold by heavy winds, maggots from the ceiling, dark nights, and haunting visitations, Mater Tenebrarum’s power was clearly evident. Rose Eliot, a poet in New York, is seen in the beginning of Inferno reading the Italian architect E. Varelli’s book “The Three Mothers”. There, she learns of the existence of the Three Mothers, who created witchcraft on the coast of the Black Sea, and how to ascertain their presence: according to Varelli, in the cellar under their house, there is a picture and the name of the Mother residing there. Suspecting that she is living in one of the buildings that Varelli built for the Mothers, Elliot writes a letter to her brother Mark, a music student from Rome, urging him to visit her. Using the clues provided in Varelli’s book as a guide, Rose eventually discovers a hole in the cellar floor, which leads to a water-filled ballroom, where she sees a portrait, obscured by the lush, foamy colors of the water, that bears the name “Mater Tenebrarum”, after accidentally dropping her keys into the water. There, she briefly encounters a putrid corpse, frightening her. She escapes, although a shadowy figure is seen watching her leave the basement.
Later on in the film, Mater Tenebrarum is seen cutting the heads of three paper dolls, which is interspersed with the images of a lizard eating a bug, a woman hanging herself, the lights going out in a woman’s apartment, and subsequently—the death of Sara, Mark’s friend, and Carlo, a neighbor, at the hands of a masked killer. As the film progresses, the Mother becomes increasingly violent: Rose Elliot is brutally murdered after seeing two shadowy figures attempting to enter her door. Her disappearance attracts the attention of her brother Mark, who has returned from Rome. Learning from Countess Elise of Rose’s strange behavior, Mark discovers blood on Rose’s carpet and decides to follow the stains, only to fall unconscious. Elise sees a cloaked, mysterious figure dragging Mark away—only to alert the killer of her presence. As she is escaping, the Countess Elise is suddenly attacked by a horde of cats and stabbed. Kamarzin, the antique owner, after an inconclusive conversation with Mark, dies: while he was trying to drown some cats in a Central park pond, he accidentally fell into the water. Hundreds of rats from a nearby drain crawl over him, gnawing at his flesh. A hot dog vendor hears Kamarzin’s cries for help, rushes over, and kills him with his knife.
Eventually, Mater Tenebrarum’s bloodlust would be her undoing. When Carol, the caretaker, discovers the horribly mangled corpse of Elise’s butler, she drops her lit candle, which starts a fire and causes her to be entangled in burning drapes and fall to her death. Mark, using a clue provided in Rose’s letter, finds a secret passageway that leads to a suite of rooms where he spots Professor Arnold, a wheelchair-bound mute. There, with the aid of a mechanical voice generator, Arnold reveals that he is, in fact, Varelli and attempts to kill Mark with a hypodermic injection, only to get caught in his vocal apparatus, choking him. Mark frees him, only to be told by the dying man “Even now you are being watched.” Chasing a shadowy figure watching him from the doorway to a lavish chamber, Mark finds himself confronting Professor Arnold’s nurse, who explains to him, with growing intensity, that she is Mater Tenebrarum. However, the fire which has consumed much of the building is adversly affecting the sorceress enabling Mark to escape. As the weakened witch gives chase debris falls and crushes not only Mater Tenebrarum, but her entire witches’ den as well, thus ending her threat.
Telekinesis-Mater Tenebrarum is shown, indirectly, locking both locks and doors to prevent the Countess Elise from escaping.
Control over Life or Death-In one sequence, Tenebrarum is shown cutting the heads of three paper dolls. With each cut, a life is shown to be ended.
Shape-Shifting-At the end of Inferno, Mater Tenebrarum transforms herself into Death Personified.
Projection into Mirrors-After Mater Tenebrarum fades, her reflection remains in the mirror.
Pyrokinesis-Mater Tenebrarum has shown to have power over fire, demonstrated briefly after her transformation.
Aerokinesis-An evil, subtle gale pervades the lavishly furnished room in which Tenebrarum sits.
Reality Warping-Mater Tenebrarum's presence completely disrupts the flow of logic and procession, as demonstrated by the incoherence of the film.
Immortality-It can be assumed that Mater Tenebrarum, along with her sisters, are over a century old.
Mind Control-Mater Tenebrarum has shown to have power to manipulate both animals and humans for her doing.
Ability to Project Powers Over Distances-Mater Tenebrarum can affect the world on a global scale with her powerful magic.