Zenon Octo and his family suffer greatly in Elphegort due to the discrimination faced by descendants of Sateriasis Venomania; his mother commits suicide when he is six years old. Left without a father, and with his younger sister Sarah to take care of, the boy uses his family heirloom, an antique sword, to mug passersby in order to fend for them both. When he turns twelve, Sarah dies due to unexplained causes; broken by this, Zenon leaves Elphegort and wanders aimlessly. He encounters an old woman in his travels and attacks her, hoping to find some food.
Some time later Zenon regains consciousness in the home of the Emperor of Asmodean, his sword missing and his body covered in burns. The Emperor hires the boy as one of his subordinates, and Zenon quickly impresses his peers with his brilliant swordsmanship. He is placed in the army and battles against the Kingdom of Lucifenia, working with the nine-year-old general Mariam Phutapie. After four years of serving the military, Zenon is given the new name "Gast Venom" by the Emperor in recognition of his service. Gast is given a life of luxury and is no longer given trouble over his heritage or youth; he mourns that he didn't go to Asmodean in time to save Sarah, the only one he could ever trust. Gast then claims that, due to this, he is glad that he has finally reunited with her.
He explains that there is a ruins site in the Misty Mountains from the Magic Kingdom era; Gast's Golden Dragon Unit, led by General Shalgham, is temporarily stationed at this site on the way to invading the Babul Desert bordering Lucifenia, an area being scouted by Mariam's Silver Sparrow Unit. Complications arise when an urgent message states that this unit may be rebelling, and the Golden Dragon Unit is camped indefinitely while waiting for orders. During this time, General Shalgham forbids the soldiers from going into the relic, being a devout Levin believer and the Altar being founded before Levin.
Gast disobeys this order and he encounters Sarah by an altar inside the ruins. Though unable to understand how she is alive, he is overjoyed and so goes on to visit her every night during the course of his unit's encampment. When questioned, Sarah asserts that she is a ghost and that, due to the powers of the altar, she can visit this world from the Hellish Yard during a foggy night. Gast does not believe this, but lets the matter drop, happy just to meet with his long lost sister.
Two weeks pass and there is no new information regarding the betrayal of Mariam's unit. Several of the soldiers are also falling ill due to unknown causes; when a war council is called, it is decided that the unit would only wait one more day to receive communication. In addition to this, General Shalgham commands the destruction of the altar, claiming it is the source of the illnesses. Gast speaks against this plan, and in response Shalgham calls him out as a descendant of Venomania. Although some of the other soldiers try to reassure him, Gast resolves in disgust to leave the army.
That night, Gast tells Sarah of all that occurred and asks her to come with him when he defects. She claims that she is unable to leave the Altar, continuing with her assertion of being a ghost despite Gast's arguments to the contrary; she then goes on to say that if the altar is destroyed she will not be able to appear anymore. Hearing this, Gast then resolves to instead kill General Shalgham. As Sarah protests, Gast sees her carrying the sword he used as a child and demands she hand it over.
The next night, Gast waits for Shalgham and the rest of his unit to approach the altar, sword in hand. From the fog, however, comes an old woman with a red cat; Gast recognizes her as the old woman that he tried to attack once before. She greets him and, when confronted, claims ownership of the sword. As Gast refuses to hand over the sword, the old woman begins to approach him and cast a spell, regardless of his attacks. She envelopes Gast in flames and he loses consciousness.
Six months after the incident, having lost the Venom Sword once again and discovered with Shalgham's dead corpse, Gast is trialed for murder, though acquitted due to lack of evidence. Nevertheless, he is made an example of for the other soldiers and exiled to prevent further rebellion. Gast visits the altar multiple times afterwards, but Sarah never appears and Gast leaves Asmodean to become a mercenary.
Some time later, Gast is hired by Elluka Clockworker to be her guard; in the process of guarding her he learns of the vessels of sin, discovering that his sword is one of them. After parting ways from the sorceress, Gast researches the sin vessels for himself and, after much searching, learns that resurrecting the dead is one of the powers of a sin vessel. In learning this, Gast remembers his experiences with Sarah at the altar and resolves to seek out the vessels of sin.
Many years later, a letter is sent to Yukina Freezis by Yvette, the head of the Held Monastery. She says that she wishes to confide her greatest regret before she dies; feeling unable to speak to Rin and Clarith concerning this, she instead will tell it to the Freezis Family as a means to thank the family for their aid to the monastery.
She tells of how she lost her father in a war at five years old; unable to remember him, her only memento of the man was a toy he gave her, a golden key that changed shape. Her mother remarried General Shalgham.
Although a more high-ranking soldier and able to give the family more luxuries, Yvette relates that he and her new stepbrothers treated her coldly and made her life miserable. Admitting she was too afraid to strike out on her own, Yvette laments that she instead did everything in her power to gain Shalgham's favor, to no avail.
One night, three guests visited General Shalgham in their home; a silver haired woman, a man with green hair, and an old woman with a red cat. The silver-haired woman gave Shalgham several documents and left. Shalgham had called her before the man with green hair; although at the time she feared she would be sexually abused by this man, she was simply told to go back to bed moments later.
The next day, General Shalgham had given Yvette documents detailing Gast Venom's history; Yvette explains that, as a pious Levin follower, her stepfather could not stand having someone descended from Venomania in his unit. Unable to convince the Emperor to discharge him, Shalgham had concocted a plan to remove Gast from the army himself, for which he needed Yvette's help as well as her stepbrothers'. Yvette elucidates that she agreed to help him, hoping that she would finally earn the love of her stepfamily through doing so.
The Golden Dragon Unit departed with Shalgham and Gast, Yvette following behind. Although Shalgham had created a false reason for the unit to stay in the Misty Mountains, the Silver Sparrow Unit's betrayal achieved the same results.
Yvette stayed hidden in the encampment during the day, and eventually approached the altar at a cue from her stepbrothers; Shalgham had forbidden Gast from approaching the altar, knowing he would disobey, and it was there that Yvette would meet him in the disguise of his dead sister, Sarah. Yvette adds that, before departing, her stepfather had forced her to carry a strange sword that would relieve Gast of any doubts he may have about her. At the altar, Gast became convinced that Yvette was Sarah, while Yvette became charmed by Gast.
In the letter, Yvette ponders over why Gast believed she was Sarah, wondering if the Deadly Sin Vessels may have been responsible for how Gast, her stepfather, and herself behaved.
Two weeks passed in the Misty Mountains, in which time Yvette fell in love with Gast, envying his strength to live on his own. In that time, the stepbrothers became sick, providing Shalgham with an excuse to order the destruction of the altar; knowing this would arouse Gast's anger, the general could then legally kill him when the soldier rebelled.
Yvette recounts how, the next day, Gast made clear his intentions to quit the army. Relieved by this, as it meant Gast wouldn't have to die, she nonetheless was too afraid to defect with him when asked. She adds that she was also too afraid to stop Gast from his plan to kill General Shalgham, and so gave him the Venom Sword when he asked for it.
The next day, Yvette tried to persuade her father to abandon his plan, telling him that Gast intended to leave; when he refused, she killed him using her golden key, her heart full of wrath towards him. Yvette notes that, without the Key, she would not have been able to kill her stepfather, a strong general, or escape from Abyss I.R and her stepbrothers. She then ran away, visiting the Asmodean Emperor only once to reassure herself of Gast's safety.
Yvette then clarifies on how she joined the Held Monastery, established ten years later; she assumed the identity of a pilgrim and met a monk, in whom she confided over her past. Under the counsel of the monk and the monastery's director, Yvette sealed away the Key and lived her life as a nun, finding peace in caring for the orphanage's children. Sometime later she learned of Gast's death in the Lucifenian Revolution and visited his grave, expressing sorrow over his tragic existence.
Yvette, having finished her confession, now writes that the Golden Key has vanished from the monastery, this fact only discovered after Abyss I.R possessed Mikina Freezis. She tells Yukina to seek the Key out and seal it, fearing that it will bring further trouble to the world.
Conceptualization and OriginEdit
- The plot of the short story was originally submitted by mothy for Entr'acte of Evil: The Daughter of Evil Worldguide but wasn't included in the final release.
- In his commentary for the story, mothy wrote a small excerpt describing how long he had wanted to write Gast's story and that to imagine Asmodean with Arabian streets, unlike Lucifenia.
- To describe Sarah's appearance, mothy explained she looked similar to Riliane, a fact Gast alludes to in The Daughter of Evil: Clôture of Yellow.