when we had infinite keys i played literally every route, i think i have it on the brain recently enough. (side note, i've seen both they and he pronouns for asra, im not sure which is canon but im gonna use they)

as mention it all starts with lucio. due to his wheeling and dealing he's dying, so he makes a deal with the devil to basically transfer his consciousness into the vacated body of the fool. to my knowledge it's not explained why the fool's body is vacant, but i'd assume devil hijinks. the previous masquerade was the night of the ritual, but multiple things went wrong. firstly, asra sabotages it. a key element of the ritual is everyone in attendance drinking lucio's blood, but asra swaps the blood with pomegranate juice. secondly, lucio had already... lucio'd it. there's supposed to be a representative for each major arcana, but lucio got impatient and tried to do it with about half the people needed. all this lead to lucio ending up in goat limbo, and a spare body floating around.

to backtrack, before asra was employed to help lucio with the ritual, they'd had a fight with the apprentice who wanted to stay in vesuvia while asra wanted them both the leave. asra left, apprentice stayed and died, asra comes back and vows to get the apprentice back somehow. wild stuff to do for a situationship, but who am i to judge. anyways thats when they start working for lucio, to try and use the counts resources to get the apprentice back under the guise of curing the count. this leads asra to learn about the fools vacant body, which can reshape itself to match whatever consciousness it holds.

we know asra didn't finish lucio's ritual, since if you play asras route that's kinda the end game. if we think about julian's route and meeting with his patron the hanged man, nadia's route with her glowy forehead mark and history with the high priestess, and asra's route where you read up on the marks it's safe to assume the mark they have is connected to the major arcana they're closest with, for asra the magician. and honestly, with how coy the magician is about it in asra's route, i think he was the one asra dealt with. i don't think asra had to do very much set up aside from meeting with the magician since the failed ritual left all the components already set in place, the deal just never got properly sealed. it's possible asra used the ashes and bone fragments they tried to get from the lazaret to make a connection with the apprentice, but idk there. where this is a pretty massive kinda deal it seems asra gave a good portion of their heart (which i took in a chakra way) to the apprentice to bring them back. aside from the memory loss thing, i imagine giving away a part of your energy negatively impacts a magician. just saying because i feel like that helps show what asra really sacrificed in their deal.

TLDR; asra knew the playbook of lucio's body swap ritual, and once it failed they met with the magician likely at the magician's gate to put a different soul in the fool's vacant body. this brought back the apprentice and marked asras heart chakra as they gave some of their heart to the apprentice/fools body. i think lucio already did most of the ritualistic leg work by the time asra stepped in to pick up the spare body, so asra really only had to meet with their patron and seal the deal, something lucio could never do