Disclaimer:This isn't so much a prompt as it is a... Story Outline? Regardless, figured i'd try my hands at outlining a cohesive story for once. Also, as the story has the girls in their Volume 1 outfits, i'm going to assume that BBTAG takes place before Volume 2.

So the story takes place about a week after the BlazBlue ending, Team RWBY have been brought back to Remnant and are stronger than ever thanks to their experiences in Cross Tag Battle, and everything is as normal as it can be after the fact.

That is, until the girls take on the Mountain Glenn assignment and Weiss, in an attempt to beat back the horde of Grimm that starts following the train filled with explosives, attempts to Summon a Grimm, only to Summon Izanagi instead.

Essentially, what happens here is that Weiss tries to Summon a Grimm she's defeated before, like a Death Stalker or a King Taijitu, only for her soul to call out to Narukami's, who willingly goes into a coma in order to allow Weiss to use his Wild Card.

Naturally, Weiss and the gang don't know this and immediately assume the worst(they don't know how the Wild Card works, and when Igor does show up he's about as willing to tell Weiss the truth as ever, which is to say, not at all. He does have his reasons though, as always).

Cue Weiss Social Linking it up in order to save the world and become a better person, all while trying to figure out how to use The Velvet Room to bring (what she and everyone else assumes is) a dead Yu Narukami back to life.

Now onto the nitty gritty details.

The story takes place a week after Cross Tag Battle for RWBY, and about a month after P5D for Persona.

No Persona/Unist/BlazBlue Characters aside from Igor and Margaret will show up until towards the very end, mostly so that Weiss isn't outshined by the older Persona users.

I don't have a solid idea on which Arcana belongs to which character but i'm pretty sure Yang is Chariot and Goodwitch is Empress. I'm probably wrong though.

Level wise, Weiss will start off as Level 20, not for any particular reason, but she sure as hell isn't starting at Level 1.

Story wise, she's actually a lot weaker than Yu and Minato, mostly because of how hard it is for her to accept the various parts of herself that make up her Sea of Souls, Fool and Hermit Personae come easily to her, but Personae of any other Arcana almost refuse to heed her call, and certain Personae will even cause her physical pain when she attempts to Summon them, like say for instance, if she were to try and Summon Hestia during the beginning of her Journey she's going to pass out, at minimum.

The Grimm are going to be hunting her down near constantly now, or rather, Salem is going to be sending Grimm after Weiss basically 24/7, because now Weiss is essentially a Maiden without the whole "If I die my powers go to the last young female I thought of as I died, and if that person isn't female or is too old, they go to some random girl out in the world" shtick going for her, which means Salem can kill her without worrying about being unable to take her powers.

Ozpin is going to go full blown Control Freak mode once he senses that Weiss has magic, and will not so subtly "Suggest" that she live out the rest of her days in a location of his choosing, which unlocks the Reversed Justice Social Link(Oz has a lot to answer for, and has done(in lore at least) some pretty fucked up shit for "The Sake of Humanity and Faunis Kind") and Weiss's ire.

At some point it's going to be heavily implied that Professor Oobleck was the original Wild Card of Remnant, but he had since then lost his powers, he'll be The World Arcana, and will regularly help Weiss decipher Igor's more cryptic advice, as well as help her learn more about her newfound (borrowed) powers.

Jacques will find out about Weiss's new powers, and he will try to get her kicked out of Beacon so he can use them for his own purposes, Ironwood and Winter will stop him for the most part, but Jacques has a lot of friends in high places, and not all of them have humanities best interests at heart.

And that's it, I really hope this is actually decent, and I hope that whoever decides to use this can make something truly amazing with it.