basically your a hashira about 20 ish years ago a event now referred to as the Join (cliche i know) occurred a portal of some sorts opened between the worlds off kny (demon slayer) and mha (my hero academia) the people just kinda accepted this and well life had to move on now going between the realities isn't completely advisable because of the time difference but it is allowed and ok as long as you know what your doing or have a guide now here's your story you a hashira met a man from the mha side and well one thing led to another and you guys hit it off started dating and are now married with a kid cut to about 15 years later said kid is now 15 getting ready for high school (no high school actually exist in kny because of the time period so he has to study in the mha side) you had just learned or well saw his quirk grew in you guys weren't sure he would get one because you obviously didn't have a quirk but his father did so yea 50 50 chances and he got one and he said he wanted to become a hero yes a hero cool you had no problem with this whole thing he applied to ua and managed to get in he was a smart kid with good grade about half the school year goes by he lives in the dorms you and your husband ren his name is live at your estate your required being a hashira to live near ubuyashiki estate so you and him have to live in the kny side doesn't matter anyway one slight thing UA is doing this sleepover thing obviously all the students will be there in the dorms but so will all the parents of the students and a few of the teachers eg all might, aizawa, and president mic obviously you're going to go you kinda have no ngl you wear attire which is common to mha's time period so you don't look crazy outta place also for clear reasons you do not being your sword very clear reasons anyway so cut to the day you and ren have arrive to the dorms by that point you take your seat say hi to a few of the other parents most people are just talking having fun i mean it is a sleep over your son his name is kai comes up to you guys give both of you a hug and says

Kei: hay mom, dad i'm glad you guys could make it

Ren: wouldn't miss it for the world

you nod and look around the 1-A girls are just doing girl stuff mostly gossip the most of guys (eg izuku, bakugo, kaminari, Kirishima, minetra) are playing a video game on the tv the teachers are talking with the parents on the couch or well all might and mic are aizawa is asleep in his sleeping bag on the floor Iida is also with the parents to no one's surprise talking as well and tokoyami si brooding in the corner again to no one's surprise