Light's Song
is a crossover between The Owl House and Supernatural, in which Luz is the much younger paternal half-sister of Sam and Dean. Raised by Bobby after her mother's murder death when she was a toddler, she ended up dragged into a number of her brother's misadventures, despite their best attempts to to keep her away from the chaos of being a Hunter. After Bobby's death, she manages to find her way to the Demon Realm, which is actually less inhospitable to her than Earth, as the constant threats to her family line can't reach her there, giving her a chance to gain a new home and family. Of course, that doesn't mean that things are uneventful...
- Adaptational Angst Upgrade: Thanks to being a Winchester in this story, Luz has been through a lot more trauma than her canon self by the time she reaches the Isles, Bobby's death just before the story starts being just the tip of the iceberg.
- She also ends up even harder on herself about inadvertently helping Belos, since she blames her family curse for causing pain to her new loved ones.
- Adaptation Expansion: The scene where Hunter cuts his hair in the middle of the night, with Willow ending up helping him fix it, is expanded on here.
- Breaking the Cycle of Bad Parenting: Bobby Singer grew up with an abusive father who would beat him and his mother. One day, Bobby shot and killed his father to protect his mother and burned his father's body in a shed, to his mother's horror. Because of his experience with his father, he was afraid to have children himself and was against having a child with his wife before she died. Eventually, Bobby would be tasked with raising the infant girl named Luz Noceda. Bobby loved Luz as his own daughter and did everything he could to raise her to be a healthy and happy person. Unfortunately, because both of them were hunters, they had to deal with danger dally, but he did everything he could to shield her from danger, train her to defend herself, and give her a normal life, and he was shown to be loving and supporting towards her growing up, making sure Luz was is fed and cared for. Bobby's death devastated Luz and throughout the story; she respected his memory and greatly missed him. Luz noted that for all Bobby's fear of being a father and not wanting children because of his abusive background, he was a loving father towards her.
- Brought Down to Normal: While Castiel can travel to the Isles due to his vessel's soul having passed on, he is unable to access his Grace while there, leaving him on the level of a human.
- Conditioned to Accept Horror: Being a member of the Winchester clan in this AU, Luz has been through a lot, and gotten used to it. Just for starters, she's died dozens of times if the time loop is counted, and at Palisman adoption day she admits that she stopped having long-term goals years ago because she accepted it as a given that she wouldn't survive to adulthood.
- Conspiracy Theorist: Jacob Hopkins, as in canon. After he attacks Hunter at a supermarket, believing that he's a demon, an employee mentions that he's banned from the store for attacking said employee with a baguette, believing that he's a cyborg drone for the Martians due to his cochlear implant.
- Crossover Relatives: In this story Luz is Sam and Dean's younger half-sister on their father's side.
- Dark and Troubled Past: Luz's mother was murdered when she was two by Zachariah (with her being left alone in the house with Camila's corpse for days), her first and only time meeting John was when he found out about her existence and kidnapped her when she was seven shortly before he died, when she was nine Hell Queen tortured her to death (including impaling her through the shoulder and causing a wound that never fully healed, even with Castiel's best efforts at it), as part of a plot to hurt her brothers, she was in the time loop with Sam and remembered the loops like he did, dying at least forty times in that instance alone... Honestly, it's a miracle that Luz is still sane, or capable of happiness at all, given what she's been through, a sentiment that Amity and Willow express In-Universe after seeing the Hell Queen memory.
- Death World: Despite the canon Boiling Isles being this from the perspective of Earthlings, the fact that this is the Earth from Supernatural means that it's more dangerous by comparison with all the monsters running around, particularly for Luz due to her Winchester blood, as most if not all monsters cannot cross over to the Demon Realm, thus rendering most of the threats her Doom Magnet status can throw at her incapable of reaching her.
- Doom Magnet: As in canon, being a Winchester means that you can barely go five feet without running into a dangerous monster and other bullshit, especially if there's more than one around for too long. Thankfully, the fact that most, if not all of the monsters from Earth are unable to exist on the Isles due to it being a realm not created by God/Chuck (for instance, angels and demons are immediately ejected from their vessels if they try to cross a portal due to the ambient magic interfering with their ability to suppress their vessel's soul) means that it's actually safer there for Luz than on Earth, despite the Demon Realm canonically being a Death World, because there's fewer threats that it can weaponize.
- Failed a Spot Check: The wannabee hunter that kidnapped Vee, believing her to be human realm shapeshifter, completely missed that she was wearing a silver bracelet (shapeshifters do not like silver, something Jody wastes no time in pointing out).
- Full-Name Ultimatum: Jody gives one to Dean when they reunite in Gravesfield over her anger at being Locked Out of the Loop, but since she doesn't know his middle name until Luz tells her she initially calls him "Dean Middle Name Winchester".
- Happily Adopted:
- After Camila's death, due to a combination of Sam and Dean being busy with hunts and wanting to limit the Winchester Doom Magnet curse around her as much as possible, Bobby was Luz's main parental figure until his death.
- Jody ends up taking Vee in, and the affection is clearly mutual.
- Luz and Eda bond a lot quicker than in canon, and before too long Eda has all but officially become Luz's new parental figure. And then later she officially adopts her.
- Hope Is Scary: Luz stopped having long-term goals some time before ending up on the Isles because she came to believe that she wouldn’t make it to adulthood due to the family curse. During Palisman adoption day, she has a breakdown over the idea that she COULD.
- In Spite of a Nail: The Hexaquad end up living in Camlia's old home in the aftermath of the Day of Unity.
- Is That Cute Kid Yours?: Due to the age gap of twenty years between them, and the family resemblance, Dean has been mistaken for Luz's father instead of her older brother more than once.
- Locked Out of the Loop:
- Sam, Dean, Cas, and Bobby all kept from Luz the fact that she was born due to angelic intervention solely to be a Sacrificial Lamb in the plans for the Apocalypse. Later, Dean keeps the fact that their safehouse in Gravesfield used to be Camila's home from her.
- Sam and Dean are terrible at keeping Jody in the loop. For instance, the whole reason that Vee could replace Luz is that neither of the brothers told her that Luz was in the Boiling Isles. When they reunite in Gravesfield, she calls Dean on it, and later calls Sam on it too.
- Hunter didn't know anything about the basilisk project before he met Vee. He suspects that it was too close to Belos's plans for the Draining Spell, so he kept it secret from his "nephew". He even claimed the reports of the basilisk attack at Hexside were a lie.
- A Mind Is a Terrible Thing to Read: Gus gets nightmares of what he saw in Belos's memories.
- Noodle Incident: Luz mentions some non-canon events from back in the Human Realm that she doesn't fully elaborate on, such as being cursed by a sock puppet to speak only in haiku or the book fair where she and Dean were terrorized by Dr. Seuss characters.
- No-Sell: For some reason the Collector's stars don't turn Castiel into a puppet, and they're unable to even stick to his skin.
- Point of Divergence: Luz is the one who has her memories damaged. In fact, the memory photos got soaked by water instead of burned.
- Practically Different Generations: Luz is twenty years younger than her bothers, and Dean was often mistaken for her father.
- Right for the Wrong Reasons: While the Hunter that kidnaps Vee is right Vee isn't human and is replacing the real Luz, it's because he thinks that she's a human realm shapeshifter, despite the fact that they can't stand silver and she's clearly wearing a silver bracelet.
- Sacrificial Lamb: It's eventually revealed that Luz herself was meant to be this, the angels manipulating Camila into sleeping with John and having her, and then having Zachariah kill Camila when Luz was a toddler so that Luz would grow up with Sam and Dean, only to get tortured to death by Hell Queen in order to drive a wedge between the brothers and get them to accept their roles in the Apocalypse, which was foiled when Castiel, who had no idea of the plan at the time, resurrected her.
- Stranger in a Familiar Land: When Luz ends up back on Earth after the Day of Unity, she finds that she's almost as out-of-place there as her witch friends are.
- Unfinished Business: After her murder, Camila sticks around her old house for a while to try and make sure that Luz was safe. When Dean showed her that Luz was happy and (relatively, given her Winchester genes) with Bobby, she passes on peacefully.
- Wound That Will Not Heal: Despite all of Castiel's efforts, Hell Queen's wound to Luz's shoulder just will not fully heal.
