that fantasy au concept is so interesting! it has such a cool emotional core with neat worldbuilding while still staying true to the spirit of the show, and just seems to... idk how to put it but it Works?
i have a metric butt load of ideas for it, some of them being:
-Lots of typical fantasy creatures like elves, dwarves, dragonborn, gnomes, orcs, etc etc etc alongside humans
-The visual aesthetic of the larger cities is strongly victorian steampunk. This is a world right on the edge of technological revolution, and as a result, oftentimes magic and those who perform it are kinda left behind and ignored in lieu of new inventions and ideas.
-Magic is something all denizens of this fantasy world can learn if they put their minds to it enough- but there are definitely some people who have an innate closer connection to the magical aspect of this world and have an easier time with it. This often runs through family lines- i.e. if a parent is a powerful witch, for example, their child will also have an innate inclination towards performing powerful magic.
-All the magic in this world is really personalized. Each individual will have an inclination towards a few types of magic that speak towards their personality and heart. It’s kinda... soul magic? So when I said the eldritch beings Rose was once a part of consume people’s souls, they’re basically feeding on pure magic.
-Rose is, of course, secretly an eldritch horror disguised as an elf. She’s like... super long-lived? She’s been around for hundreds upon hundreds of years in this world, far beyond the normal lifespan of elven folk. However, she flies under the radar and is never really questioned because everyone just assumes the immense power of her magic is what’s keeping her alive. She deals very deeply in eldritch magic, and also boasts considerable healing/restorative powers. She’s still alive when Steven is born, and is loving as a mother, but... she tends to be very reclusive, and starts to keep him at arm’s length the older he becomes. (see: she’s super stressed and distracted about trying to find a way to save this realm when her ward fails in a few years.) This may be an AU, but Steven still gotta have mommy issues.
-Pearl is her first love, the elven woman she fell for when she first came to protect this world. Rose has granted her long life, afraid to see the people she loves die. Pearl is a skilled fighter and mage, able to show others impeccably accurate visions of her memory in a cloud of smoke, conjure an illusionary version of any item she’s seen, and even summon light soldiers to cover her.
-Garnet is another early friend she made, during that initial fight against the eldritch beings trying to consume this plane of existence. Garnet has also been granted the power of long life. She is a clairvoyant seer who can see potential paths of the future, but while she uses this power she temporarily goes blind as she accesses her “third eye,” so to speak. As a result, this is a magic she must use wisely, outside immediate dangers. Haven’t decided what fantasy people she’s of.
-Amethyst is a young human girl these three came into care of much later, someone without a home to call her own. She’s scrappy, and is adept with forming illusions and shapeshifting. Her magic is very handy in conflict with distracting and disorienting others, and is also fun for cheap tricks to get a laugh. These days, it’s a rare day she’s NOT in some shapeshifted form.
-Greg is a human, and he’s absolutely a bard :D Most of his magic he actually learned from Rose, as his parents didn’t allow him to seek out magic training when he was a kid under their thumb.
-Connie is a human who lives in one of the larger cities of this world with her parents, and she quite literally ran into Steven in the streets one day... which eventually lead to them striking up a close friendship and their stories intertwining. She’s always wanted to study magic, but as of late, with all the technological revolutions, texts on it are becoming harder and harder to find. Magic is becoming something that is more often only passed down within families... something unfairly insular. Neither her mother or father are innate magic users, so she has no one to teach her. No one, that is... until she met Steven and his family. Steven... who is the son of the literal most AMAZING sorceress who ever walked this world.
She is a quick learner, and over time picks up some mid-level telepathic abilities- which allow her to poke into people’s inner thoughts at will. She also becomes adept at scouring information- magically soaking up words in a book like a sponge, and at sensing hidden sources of magic many others cannot. She trains with Pearl as a swordfighter, as well.
-Steven... genuinely believes he is a half-elf for most of his childhood. His mother is an elf, of course, and his father a human. He’s got pointed ears like his mom, and shares her natural magical aptitude. However, since he is actually half-eldritch instead, there’s a lot of very, very subtle, unusual physical quirks about him he doesn’t know to mask, some of which are:
His eyes shimmer with little pinpricks of light occasionally, almost as if an entire galaxy were encapsulated within them. This only happens when he’s feeling very strong emotions. It’s not something anyone would notice unless they were looking for it.
Sometimes... rarely... when you look at him close, it’s as if for a brief glimmer of a moment his form feels off. Like something’s missing, or your sight is somehow glitching. Like there’s something about him you can’t quite see.
He doesn’t feel warm to the touch, nor does he feel cold. The closest description of sensation I could make for what someone feels when making contact with him is like... TV static.
If you know him long enough, eventually you’ll grow to recognize a slight dissonant harmony within his voice. It’s very subtle, but always there.
These quirks are things Rose shares, but knowingly masks. Every single day she doesn’t tell him the truth about her origins is a day she fears these quirks will grow so strong it’ll put him in danger, but what’s even more dangerous is the thought of having to burden him with her secret, and... likely have to deal with the fallout of everyone discovering that she’s lied about what she is for all this time.
Steven’s magic is heavy on abjuration. He’s very adept at summoning barriers and shields and at casting all sorts of defensive spells. He can also bring plants to life, but this is incredibly draining for him earlier on in his magic training. He’s got a bit of healing ability, although nowhere near his mother’s, and he’s also a strong empath. As his power grows, so too does the strength and longevity of his shields and creations. However, along with that, his empathic abilities become so powerful that he often finds himself overwhelmed by the emotions of people around him. He’s largely unable to just “turn it off,” and thus prefers to stick to peaceful, secluded areas rather than trundle through highly populated areas all the time. Music is a really good diversion for him when he feels too overwhelmed by everyone’s emotions.
-At some point, Steven and Connie come to question Rose’s secrecy, and pry into what she’s doing a bit... Connie attempts to use her telepathy to peek into her surface thoughts, and... hoo boy, that’s not a super wise move on Connie’s part, because Rose can feel this girl picking around in her mind. The two of them get into big trouble, as Rose is terrified at people discovering her true identity at this point, at people learning about the truth and then pressing into her dangerous world. While she doesn’t intend to be, Rose gets kinda... scary when she’s upset. Don’t upset her.