Demascus was a deva from the world of Nerath who operated in multiple realities, including the universe Toril was located in. He was called upon by the gods to set straight things that should never have occurred. Demascus was often killed on his missions but was always resurrected with little memory of his past incarnation.
At some point prior to the Spellplague, an incarnation of Demascus performed an important task for Mystra in Halruaa. While in Halruaa he became romantically involved with a human named Madri. For unknown reasons, he was ordered by a deity to kill Madri which he did. Memories of Madri continued to haunt Demascus' dreams from time-to-time.
Demascus was tasked by an avatar of Oghma to stop a heretical branch of his church from using the Damos artifact that allowed its user to see into the future. In 1475 DR he was attempting to stop a cult ritual in the Akanapeak Mountains when he was slain. In 1479 DR he woke up in a new incarnation at the site of his previous death and made his way to Airspur.
While in Airspur he had a chance meeting with a pawnbroker named Chant Morven. Unknown to Demascus, his previous incarnation had left a powerful magic scarf with the pawnbroker for safekeeping. Immediately after Chant returned the scarf, it was stolen by a rogue named Riltana. Demascus and Chant tracked Riltana to the Sepulcher, a secret cave complex behind Akanawater Falls, and retrieved the scarf. Riltana agreed to help Demascus track the demon he believed he was intended to destroy.
The trio had hear rumors that the Firestorm Cabal was conducting dark rituals so they went to the organization's headquarters at the Motherhouse to snoop around. They bluffed their way into a meeting with the cabal's lieutenant. The cabal was attempting to track down recent demonic activity in Akanûl and Demascus agreed to investigate a wizard named Chevesh who had a reputation for conducting forbidden experiments. This lead proved fruitless and the trio returned to the Motherhouse to find that it had burned to the ground while they had been away.
Riltana used her friendship with Queen Arathane's niece, Carmenere, to obtain an audience with the Queen who instructed Demascus to investigate the ruins of the Motherhouse. While exploring the vaults beneath the Motherhouse, the group found members of the Cabal who were involved with the Cult of the Elder Elemental Eye. The group was taken prisoner by a demon named Murmur and were about to be sacrificed but managed to escape and kill Murmur.
One of the Firestorm Cabal cultists named Jett escaped and was tracked by Riltana to his home in a large estate. Riltana discovered Jett was in reality a rakshasa named Kalkan. She brought Demascus and Chant to the home and they traveled together through a portal that led to the tomb of Demascus' previous incarnation. At the tomb he recovered his magic greatsword but was ambushed by Kalkan. Demascus managed to kill Kalkan thus fulfilling his contract with Oghma.
In Leafall of 1479 DR, Queen Arathane asked Demascus and Riltana to investigate potential trouble at an arambarium mine on Ithimir Isle off the coast of Akanûl. While investigating, they stumbled upon a drow plot to steal arambarium lead by a priestess of Lolth from Menzoberranzan named Chenraya Xorlarrin.
Demascus, Riltana, Arathane and Chant and Jaul Morven sailed to Ithimir Isle and fought Chenraya and her minions. During the battle, Chenraya collapsed the ceiling on Demascus but he was able to escape with the help of Madri. Unfortunately, the drow were able to transmute the arambarium into a staff and escape. The group traveled back to Airspur and entered a portal to the Demonweb Pits in the catacombs just as Chenraya was completing a ritual to open a gate to Menzoberranzan. Demascus interrupted the ritual and grabbed most of the arambarium staff from Chenraya as she entered the gate.
Because he had not recovered his memories from his previous incarnations, Demascus was unsure of all his abilities. However, he could cloak himself in shadows and shadowstep. He could also channel angelic power through ordinary swords.
Demascus was tall and slender with pale skin and white hair. He had ash grey tattoos on his arms, shoulder and back.
Demascus possessed the Veil of Wrath and Knowledge, the magical greatsword Exorcessum, and a scroll-shaped charm that tells truth from falsehood. Past incarnations of Demascus possessed the Whorl of Ioun ring, though it went missing. The veil had many functions—it claimed to be a "filter of Fate" and could communicate on occasion, provide light, information, and could serve as a garrote. The greatsword stored a variety of different powers in its runes, few of which Demascus recalled. The Whorl of Ioun retained memories he would otherwise forget when he reincarnates. However, the Whorl's store of memories were mostly of Demascus's once-vast abilities; the ring wasn't a deep reservoir of personal memories, and contained only a thick enough thread of remembrances to maintain the Sword of the God's continuity of consciousness.
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