The Serpent’s Vow is a crossover fanfic of Yu-Gi-Oh! & Stargate SG-1 written by Rahar_Moonfire.
While at a technology and gaming convention in Seattle, Yugi and Joey ask Seto Kaiba for help in retrieving Honda, who has been kidnapped and brainwashed into the cult of Seth Fargough. Unbeknownst to either Yugi or Joey, Seth and Seto have ancient and unpleasant history together. Things only get more complicated when a certain wormhole-traveling military team get involved...
Aside from a few backstory changes (the most notable being that Seto Kaiba is and always has been a Goa’uld), the fic is otherwise (mostly) canon compliant up to the events of Duelist Kingdom and "Seth", at which point things start diverging.
Also has a pseudo-Sequel, Dragons of Atlantis
, which is a fusion fic of Stargate Atlantis and the Doma arc of Yu-Gi-Oh!, as well as The Serpent's Reflection, which is told from the perspective of Dr. Samantha Carter after the fanfic's version of the events from "Point of View". The Serpent’s Vow can be found here and here.
The Serpent's Vow contains the following tropes:
- Adaptational Backstory Change: Seto Kaiba is changed from being an orphan who was adopted by the CEO of a weapons manufacturing company along with his brother to being a 5,000 year old Goa'uld Queen who aided the Pharaoh in driving the Goa'uld off the Earth, who was later adopted by the CEO of a weapons manufacturing company along with another kid from the orphanage.
- Adaptational Badass: Downplayed with Seto, who has several thousand years' worth of various martial arts experience.
- Adaptational Jerkass: Joey's mother comes across as this, having willingly left Joey in the care of his alcoholic father.
- Adaptational Nationality: Katsuya "Joey" Jonouchi is half-Japanese/half-American.
- Adaptation Dye-Job:
- O’Neill’s eyes are described as being green rather than brown.
- Pegasus's hair is referred to as "white". In canon, it's grey.
- Adaptation Expansion:
- Walter Harriman's family is a little more fleshed out here, building on what little information was provided about them. His sons—one of whom wants to be a dancer on Broadway, the other wants to join the military—are named Andrew and Mark; both are around sixteen years old. His wife is named Charlotte.
- Isis and Osiris are given slightly more development; Isis in particular is described as being something of a scientist, conducting experiments similar Nirrti's.
- Adaptation Name Change: Subverted, Nephthys was merely an alias that Seto used and never was his real name.
- Adaptation Species Change: Seto Kaiba is a Goa'uld. In canon, he was human.
- Adapted Out: Zorc Necrophades appears to be absent, his role as a backstory antagonist is replaced by Ra specifically and the Goa'uld in general.
- Ambiguous Gender Identity: SG-1 feels quite uncomfortable around Seto, who belongs to a genderless alien species yet assumes a female sexual role and has a male host. Seto's horror at the prospect to lose his current body had led a few viewers to ponder the possibility of him being a transgender man.
- Anachronism Stew: Mostly averted, although Joey derisively refers to a cultist as "Magic Mike" in 1999.
- Ascended Extra: In canon, Walter Harriman rarely did anything besides
dialing the Stargate. Here he is either the focus of or a major player in several scenes, up to and including intervening in the possessed Joey-vs.-Yugi duel. - Asskicking Leads to Leadership: Thanks to a combination of his luck and fighting skills, Joey is made Seto’s first prime.
- Backup Bluff: Seto boasts to Seth that he’s been building an army over the past five thousand years (when no such army exists), and that SG-1 are a part of said army.
- Bad to the Last Drop: Seto thinks that the SGC's coffee is awful. He drinks it anyways.
- Bizarre Alien Biology: According to Seto, the Furlings synthesized Orichalcum in much the same manner as the Goa'uld synthesize Naquadah.
- Born Lucky: Joey.
- Breeding Slave: Goa'uld System Lords tend to imprison queen symbiotes in a tank to breed and spawn until they die from exhaustion. Because of this, Seto is rather cagey about allying with another member of his race — and he's not really wrong, since even the Tok'ra are interested in his fertility.
- Casting a Shadow: Seto uses the Millennium Rod to control Shadows.
- Clingy Macguffin:
- Seto notes that no matter how often he threw the Millennium Rod away, it always found its way back to him.
- Ishizu admits that not long after earning the right to wear the Millennium Tauk she buried it in the sand not far from her home, only to find it the ground near her bedroom door when she went to bed later that night.
- Composite Character: Set and Seto are the same person. Daniel Jackson also realizes Nephthys is an alias of his.
- Cool Big Bro: Mokuba thinks of Seto as this, even when he realizes that Seto isn’t human.
- Cool Bike: Seto’s bike has a biometric lock that will electrocute anyone unfortunate enough to try to tamper with it.
- Crossover: Between Yu-Gi-Oh! and Stargate SG-1.
- Dead Fic: The fic was last updated on June 30, 2020.
- Death by Adaptation: Yugi's father is mentioned in passing as being deceased.
- Decomposite Character: Daniel Jackson understands that Egyptian mythology was so inconsistent regarding Seth's characterization because two Goa'uld laid claim to the name — Setesh that accounts for the pure villainy, and Seto that was a chaotic yet staunch ally to mankind.
- Dies Differently in Adaptation:
- In canon, Gozaburo Kaiba commits suicide by jumping out of a window. Here it initially seems like he dies the same, only for it to be strongly implied that Seto used his Shadows to push Gozaburo out the window.
- In canon, Mr. Ishtar dies either from being skinned alive by Yami Malik (manga) or being stabbed to death by Yami Malik with the Millennium Rod (anime). Here, since Seto has been in possession of the Millennium Rod for the past five thousand years, Mr. Ishtar instead dies when a Goa'uld-possessed Malik throws him into a wall, breaking his spine and shattering his skull in the process.
- Distressed Dude: The fanfic opens on Setesh's cultists brainwashing Honda into a servant, and Seto going to help his friends with the rescue puts him on SG-1's radar.
- Does This Remind You of Anything?: Setesh refusing to call Seto by another name than "Nephthys" (a pseudonym Seto hates) and threatening to deprive him from his host is rather uncomfortable if viewed through a LGBTQ lens, as Seto could be interpretated as a transgender man desperate to not go back to a more submissive and feminine identity.
- Everyone Has Standards: The Tok'ra are utterly sickened to learn Seto was implanted into a toddler when he still was immature enough to be around his host's age-range in development, with Selmak openly calling it a crime.
- Eunuchs Are Evil: Heru'ur, since Seto cut off the former’s penis at some point during the Goa’uld occupation of Earth for trying to make Seto his breeding queen.
- Fusion Fic:
- Osiris takes on the role originally fulfilled by Yami Malik.
- Atem was the Pharaoh who led the uprising against Ra.
- Groin Attack: SG-1 all find it amusing when they learn what Seto did to Heru'ur, but Jack in particular is still uncomfortable at the imagery.
- Ignorant of Their Own Ignorance: Seto was unaware of the existence of the Tok'ra, the Protected Planets Treaty, and the death of Ra until he met General Hammond. On a personal note, he also believed that it was impossible for the host's mind to survive implantation simply because his own host has no consciousness of its own, when that is actually due to him being implanted so young that his host never had the chance to develop its own identity.
- Internalized Categorism: Name-dropped by Yami when Kaiba blatantly accuses the Goa'uld from being pure evil, including himself in the lot.
- Named by the Adaptation:
- Mokuba’s surname prior to being adopted is Takahashi. This is a mythology gag,
being a reference to Yu-Gi-Oh! manga author Kazuki Takahashi. - Seto's mother (the mother of his host and the woman who raised him) is named Heket.
- Mokuba’s surname prior to being adopted is Takahashi. This is a mythology gag,
- Noble Bird of Prey: Neith, whose host is a white-tailed kite.
- Only You Can Repopulate My Race: The Tok'ra really want for Seto to join their faction, as a fertile queen would replenish their ranks. Of course, Seto isn't very happy when people get interested in his ability to spawn broods...
- Patchwork Fic: The fic seems to be set in a fusion of the manga and the Sub continuity of Yu-Gi-Oh! (there's a remark about the time that Shadi rearranged Anzu's soul room and Yugi is taken to the hospital because of a warehouse fire caused by Bandit Kieth). Additionally, the Shadow Realm is referenced as being the place Duel Monsters are summoned from, and several characters (Serenity Wheeler, Katsuya "Joey" Jonouchi, Isono Roland and Saruwatari Kemo) have names that are either fully or partially the versions they had in the Dub.
- Reincarnation: Aside from being reincarnated into Ishizu Ishtar, priestess Isis has been reincarnated at least two other times to her knowledge.
- Related in the Adaptation: The Goa'uld queen that spawned Seto is none other than Isis.
- Share the Male Pain: O'Neill's reaction when he learns Seto publically castrated Heru'ur is balanced between horrified surprise and proud disgust.
- Shout-Out:
- Take a Third Option: The entrance of SG-1 into Setesh's compound gives Seto a chance to do this, the other two options being submitting himself willingly to Setesh (keeping his host in the process) or refuse and lose his host.
- This Is Reality: Walter Harriman refuses to try and defuse a bomb in spite of Kaiba's insistence he can do it, snapping a backgroung in computer science doesn't mean he's qualified for this kind of work and "this isn't Hollywood".
- Undying Loyalty: Seto is this towards his Pharoah.
- Unrelated in the Adaptation: Seto isn't biologically related to Mokuba in this fic. It doesn't stop them from loving each other as if they were, however.
