Curate, connect, and discover
I really really enjoy ageswap AUs and would love to take a crack at one myself honestly. It's fun seeing different ideas and takes on things, and I like seeing kid Reigen being a little shit. So I keep thinking about how Serizawa in canon is essentially what Shigeo would be like had he not had Reigen to help him out as a kid, and so in an ageswap au I can see Shigeo ending up a hikikomori, never leaving his room/apartment for anything other than perhaps the barest necessities.
Perhaps one time on a short, midnight run to the local 24/7 convenience store to stock up on food for the next few weeks, Shigeo sees something, just close enough to notice the movement out of the corner of his eye. Some kid with a mop of blond hair turned a dull silver in the pale moonlight and luminescent street lamps lurking around alleyways armed with a bag of salt, saying something about melting evil spirits.
It's an odd sight, but it's none of his business. He wasn't expecting anyone out at this hour, which is why he went out for food at this time, so he moves to leave, just go back home and not go out for the next long, long while.
And then an actual evil spirit shows up, making Shigeo's hair stand on end from the sudden burst of spiritual energy, and the kid makes a startled noise that catches his attention. There's not a lick of psychic energy in that kid, and there's a rather nasty spirit looming over him. It's not like Shigeo can just leave him be, the table salt the kid is violently throwing isn't even doing anything. He could get hurt.
The spirit ends up exorcized, perhaps a bit more explosively than Shigeo would have liked but it's been a long time since he used his powers. Of course this catches the kid's attention, and when said kid turns around to notice this haggard looking man in pajamas at 1 AM with convenience store bags and standing near the entrance to a sketchy alleyway the kid decides that clearly the best course of action is to run directly up to him and start chattering about "Did you do that?! Are you a psychic?!" Shigeo tries making a run for it but this is a man who barely leaves his apartment and hasn't exercised since he was like 13 or 14 for PE classes so the kid catches up embarrassingly quickly.
The kid enthusiastically introduces himself as Reigen Arataka; Rising Star of the Psychic World and soon to be Greatest Psychic of the 21st Century. The kid, Reigen, goes on and on about how he was looking around for an evil spirit he's heard about from classmates at Salt Middle and from gossiping housewives he's passed by, and obviously since spirits are more active at night it's a great idea to go looking then.
And since Shigeo's a psychic, that means he has to teach this kid how to use psychic powers. Obviously.
Shigeo is not thrilled at the idea. Using his powers right then was a one time deal and he's not going to use them ever again because he'll explode and hurt everyone and-
But Reigen's not going to take no for an answer, he gives Shigeo a card for a sketchy looking business called Spirits & Such, run by one Kurata Tome. Reigen says that's where he's working after school and on weekends, and that he'll be taking Shigeo there the next day. Somehow, Reigen manages to get Shigeo's name and address from him before prancing off into the night like it's a totally normal thing for a what, 13?? year old to be doing. Shigeo goes home for the night, that was way too much interaction for him for the next decade. And it's not like that kid will actually remember this and show up at his apartment, right?
Shigeo wakes up to insistent rings of the doorbell some time in the afternoon, and he's content to just not answer but damn that is loud and persistent and just wont stop ringing so he begrudgingly cracks the door open to find Reigen in all his like 5'1" glory ready to drag Shigeo out of his apartment and to Spirits & Such, calling him Shishou all the while.
So it turns out this Kurata person recognizes his name as that kid who refused to join her Telepathy Club in Middle School, which is awkward. Shigeo's not quite sure how he got here, getting a job and a makeover even (Kurata insisted she cut his hair rather than let Reigen handle the scissors) but Reigen's persistent enough that he finds himself falling more into a routine working at S&S, and it's... it's nice, actually. He's finding his anxieties quelling and himself relaxing more, and talking with Kurata and Reigen isn't all that bad. He's getting himself back on his feet. Reigen is impressive with how he speaks with customers and a part of Shigeo wishes he could do that, wishes he could speak so clearly and understand people so easily. He's working on it, bit by bit.
And then he finds himself questioning his life choices because of a spirit haunting an all-girl's high school, shutting down a cult and gaining a sentient fart cloud as a companion, running into a TV celebrity who happens to also be an esper, and a whole lot of other things go down that leaves Shigeo's head spinning.