Summary:

Kageyama Shigeo has pink hair, but that's not all. He's an honor student, a sports team captain, a compliant son, and a loving older brother. Shigeo wants nothing more than to maintain this wonderful life. But with his younger brother, Ritsu, seeking more indepedence, Shigeo is forced to navigate through interpersonal relationships to understand why people want to change, and why he doesn't.

Character swap between Mob Psycho 100 "Kageyama Shigeo" and Disastrous Life of Saiki K "Saiki Kusuo." Takes place in a hybrid world in the setting of Jujutsu Kaisen (you don't have to be familiar with this series.)

(Formerly known as The Older Brother of the Psychic's Little Brother, now in series format. Summary has been updated; story remains the same. Read End Notes in Chapter 1 for elaborated story notes on warnings and ships.)

Story Notes:

STORY AND CHARACTERS

1) What are the ages of the characters?
The story starts with swap!Kusuo and Ritsu being 12 and 11 respectively, a sixth grade and a fifth grade elementary student. A lot of the story will take place during middle school and high school like the canon worlds of Mob Psycho 100 and Disastrous Life of Saiki K.

2) What are the POV's of this fanfic?
The four bro's, Shigeo, Kusuo, Ritsu, and Kusuke will have first-person perspective. Other characters may have POV chapters, but they will be in third person.

3) When do the Kageyama/Saiki perspectives start?
- Swap!Kusuo (Shigeo) starts at Chapter 1.
- Ritsu starts at Chapter 3.
- Swap!Shigeo (Kusuo) starts at Chapter 6.
- Kusuke's perspective won't start until Chapter 15+ by my estimate.

4) When will the other Mob Psycho 100 / Disastrous Life of Saiki K supporting characters have roles in the story?
Swap!Shigeo (Kusuo) arc as he enters first year of middle school.

5) How long will this fanfic be?
A novel series. Maybe a trilogy.

6) Why are the characters very different from their canon?
The narrative will favor another aspect of them from time to time in relation to the current conflict of their story. The similarities and differences are actually very big hints in this story. Some may seem the same as canon, but they are actually not. Some may seem different, but they are actually the same. I hope folks look forward to discovering them! A lot of things in this story are not what they seem at first glance.

7) Why are there other characters from other shows?
I don't like using OC's in fanfics, and I am a huge fan of supernatural series. I'll be plucking them for this story's use to my convenience. I also like including more representation when possible.

RELATIONSHIPS

1) Is there romance in the story?
Yes.

2) Is romance the focus of this story?
No; however, there are characters whose current goal is on romantic engagements, so chapters about them may seem romance-focused. As part of the coming-of-age tag of this story, many of them are figuring out relationships.

3) What are the ships in the story?
F/F, M/M, F/M. Gay, bi, ace (not in any order). I can't emphasize enough how much I adore coming-of-age stories, and the sort of journeys of finding yourself. You will definitely read that here.

4) What are the character ships in the story?
I cannot disclose it due to spoilers. Only thing I will say it there will be crossover character ships. If you dislike that, that's the only warning I can give.

5) Is there incest (or step-incest) in this story?
No. This includes completely wiping any reference, jokes, or implication of it such as with Teruhashi Makoto. The gag doesn't work well in this universe, and serves me no purpose whatsoever.

WARNINGS AND TAGS

Major Character Death: I'm not decided at all with this yet. I won't know until I am in that scene, or approaching the moment. So this tag is here just in case.

Dark Fantasy: There will be reoccurring themes and references to the occult. This includes practices that are violent such as demonic possessions, mass killings, human sacrifices, and cannibalism. There will be NO sexual violence or occult practices relating to sexual rites.

Fantasy Violence: All graphic violence in this story are of a fantasy nature. It involves supernatural and non-human beings, like spirits, sorcerers, and psychics.

Slice of Life: This story heavily focuses on interpersonal relationships and conflicts.

Author's Notes:

In this story, the Saiki Kusuo you know is "Kageyama Shigeo", and the Kageyama Shigeo you know is "Saiki Kusuo". This an alternate universe, so there are other relationships that are different. This isn't just simply a switch premise that would follow after the original series plots, so prepare for an original story!

Story cover commissioned from artbyyellie in twitter, exclusively for my use only!

Chapter 1: Not Using Pyrokinesis to Start the Fire

KAGEYAMA SHIGEO

A question - one rather unusual - is what starts it all.

"Nii-san, how do you know you're the strongest person?"

It might not sound as strange without knowing me personally but see, I am truthfully the strongest person. Power that comes with fortune, beauty, influence, position, belief or legacy - none of that human intricacies apply to me. There is no deeper meaning whatsoever. I can destroy humanity in a month if I really tried.

My parents are unhappy when I say this fact. They don't appreciate "jokes" done in poor taste. Not particularly about the destroying part, by the way. If I said I could bring about world peace, they would have not said differently. "The world is much bigger than you think," I would be reminded. "It's good to have big dreams, but you should focus on your studies first."

They don't grasp that the unusual pink-haired son they raised for twelve years is truly an entity that could bring humanity to its knees.

Mom has a disapproving frown as if she had witnessed me picking on Ritsu. "Enough already. Shige, this isn't how an older brother should act toward his little brother. You're both still kids, but you're the older one. You have to be careful with words."

"No, it's my fault, Mom. Sorry." Ritsu is quick to smile and apologize. Day by day, my little brother is increasingly becoming tactful. Rather than have me shoulder the blame, he redirected it to himself for asking. Though, being the older brother, I'm never off the hook.

"Look at that, Shige. Even Ritsu is covering for you."

"But Mom, Nii-san has always been top of his class," persists Ritsu, forgetting his dinner. "He's captain of the judo club, too. Teachers are already asking if he's considering enrolling in a private high school."

"Of course, Shige's impressive," agrees Mom fondly, her wrinkles loosening.

"Then that makes you the strongest, Ritsu!" says Dad with a laugh. Ritsu's eyebrows scrunch in confusion. "You're top of your class, too, and you've beaten every record Shigeo set."

"I'm sure Nii-san could have done more if he wanted." He sends a meaningful glance my way, his smile returning.

Mom can't deny our achievements. The house is full of certificates and trophies, and pictures commemorating award ceremonies that Mom deeply enjoys dusting everyday. "I suppose Shige is still setting a good example. But don't go overboard telling Ritsu all sorts of exaggerated tales."

Dad regards me with a grin. "Ritsu loves his brother too much, but don't push yourself too hard."

Pushing myself? I wouldn't know how that feels. Still, I agree with Dad. "Ritsu."

Ritsu looks at me, and smiles widely at the pork I added on his plate. "Thanks!"

My little brother does love me. It's as true as I am the strongest. Between those two, only one of them really matters.

"You don't have to apologize," Ritsu tells me as soon as our parents are gone while I'm by the sink washing the dishes.

I used to hate having to make Ritsu look like a liar. I still do to some degree, but he shouldn't have to apologize on my behalf. Ritsu has taken it on himself to initiate, so I wouldn't be able to repeat the same mantra of apology. It's still on my mind to despite knowing he's heard it (and expecting it) before already.

"It really was my fault asking in front of Mom and Dad though," continues Ritsu, reaching on the wet plates to dry them. "I thought Mom would be okay with it."

It 's been years since she saw me use my abilities. You were seven, so that would be four years ago.

"That's not a long time. Not to mention, she was really into them too. We used to exchange notes back then."

Back then, it was still all fun and games. I smile, still finding the memory of Ritsu getting genuinely angry at Mom when she wouldn't agree with him about the radius of my telepathy to be quite funny. It's just so rare to see Mom be adamant.

The thought of "strongest human" never came across our minds. Now, I'm just an ordinary, excelling first-born son to her, who will continue to succeed up through high school and get into a prominent university.

"You'll always be amazing for me," says Ritsu. I put my hand on his head, which Ritsu swats away because it's wet from the dishes. "Hey!"

He's pouting. What kind of older brother wouldn't want to pat him?

Is the excelling first-born son part not amazing enough? I ask with a chuckle.

"I can do those too. It's not that hard," he points out, combing away the water droplets. It's nothing compared…

My attention wanes as I let the rest of Ritsu's thoughts merge into the constant, noisy buzzing in my head. I have already become desensitized to the endless whisperings, and twelve years with telepathy, growing in range every year, has allowed me enough skill to pick through them. It's at least good in helping me not hear thoughts of those close to me. It still takes a bit of focus, since I have to get into a state of - ironically enough - spacing out.

Of course, my little brother is used to this by now. No pausing or questions asked. It's almost psychic how he seems to have picked up on small cues even I'm not aware of. He taps me on the shoulder, picking up the rest of the dishes. "I can do the rest. You go take a bath."

It's just dishes. I pick the dirty dish from his hands. Ritsu and I are only a year apart, so it doesn't have anything to do with being the older brother. It won't look good for the strongest to be too tired to do the dishes.

"That's not what I meant," laughs Ritsu, turning to lean back on the counter.

Ritsu doesn't elaborate, and when I try to slightly focus, not the slightest murmur passes through his mind. Ritsu is incredibly smart and curious. The questions he's asked when we were kids can take up an entire novel, and I suspect they've only thinned out through the years since he's exhausted them. Exhausting for me, as well, but I never complained. I don't have anyone to talk with about my psychic powers. Ritsu's enthusiasm relieved my own tauted thoughts and feelings.

Then what did you mean? I ask.

"Well, how do you know?" repeats Ritsu, contemplative. "Did you assume you're the strongest, or have you made certain of it?"

Made certain? How was I supposed to do that?

You mean, if I fought against people? If I did something like that, then there would be a mass panic I might accidentally hurt them and destroy cities too. I don't want the countries throwing a fuss.

"Yeah, but obviously, ordinary people won't do. I'm talking about other psychics. There are others like you, right?"

There are.

The confirmation perks Ritsu's interest. Why the surprise when he seemed certain there are other psychics? If he were expecting some shounen manga-level story to tell, he'll be disappointed.

I don 't make contact with them. As long as they don't cause us trouble, I won't bother.

"Why not?" asks Ritsu immediately.

I turn off the faucet and dry my hands before staring at Ritsu levelly. Is there a particular reason I should?

Ritsu blinks. I can see the bewilderment all over his face, which makes me wonder if I'm the confused one as he stutters, "Because - you'll have someone like you! Someone who understands what you're going through. You can help each other out with your problems…"

There are other psychics, but none of them are on my level. They won 't be of use to me. Being a psychic is irrelevant anyway.

Ritsu frowns. "Irrelevant?"

Ritsu used to be much more carefree when we were young, but he would get tense like this sometimes. He never did like not knowing or understanding things, but it's hard to believe how oblivious he can be. "I have you, don't I? Someone who understands and helps me out."

He purses his lips, glancing away and unconvinced. "I'm not doing anything special." Nii-san is just being nice again.

"It's the truth!" I'm not upset, but the fact that Ritsu doubted me unexpectedly roused me. Ritsu flinches, realizing that I overheard his thoughts. "I - "

"Sorry," he blurts out, ashamed, and runs upstairs.

My own apology fades out in the air. How is it that Ritsu keeps beating me to it every time?

"Not using pyrokinesis to start the fire, Nii-san?"

We have been camping in the same mountain for half mine and Ritsu's lifetime now. Other families with similar budget have done the same, so we practically grew up with their children, meeting annually before the new academic year. With my ever-growing abilities, it's become harder to control them. I imagine if I try to light the camp with pyrokinesis, I would unleash a fireball the size of a watermelon.

Ritsu, my little brother, is aware of this of course. If something unexpected happen, I'm sure I can work it out but is it worth getting a scolding? Not to mention we're not alone. That loud, whining half-German kid who joined the group last year was around blasting American music.

"He's not paying attention," remarks Ritsu innocently and crouches down beside me, speaking in a lowered voice my hearing aids pick up acutely, "I overheard his mom talking to Sato-san. He called a girl ugly and refused to apologize."

Say no more.

I flick my finger out, shooting a concentrated heat beam at the logs. The change of colour is immediate but when they don't burst into flames, I know something is amiss. The logs implode and in their place is a spinning, fiery wisp. I have accidentally created some form of energy. I stand back instinctively, not realizing it's linked like a string wrapped on my finger. As the wisp lobs into the air, it breaks into a shower of embers, alighting a tree right in front of the half-German kid. Ritsu is pounding my shoulder urgently before I can freeze the tree in panic.

Too suspicious! Pull it out - use telekinesis!

I don't know how that's supposed to be less suspicious, but I already have misgivings about my cryokinesis. I may end up freezing the entire camp with a wrong move. If Ritsu thinks telekinesis is better, I jump on the idea. Out of my sight!

The full force of my telekinesis warps the burning tree in a deformed blur that's out of this world, shooting into the sky and vanishing before you can blink. It doesn't gain much altitude; it disintegrates from what must have been faster-than-sound travel. On the ground is its roots left untouched, the soil without any mark while the surrounding trees have bent backward unnaturally, as though they have turned elastic.

We hear what we can only assume was the German version of "What the heck" as the fellow camper Ritsu and I don't like stumble off his lounging chair, his hood slipping out to reveal a head of spiky orange hair.

"Mom! Mom!" he screams, frantically standing up. He does a double take when he finally notices us. "Hey - you two, did you see - what? What's with you two?" he demands, very agitated.

Ritsu and I put on an identical, clueless look.

"Honestly! I don't know what to do with you two," sighs Mom, exasperated and deeply disappointed.

"Let's talk about it when we get home," says Dad, putting a hand on Mom's shoulder. He's just as disappointed in us, which hits worse since he's usually indulgent.

"It's fine, Mom. No one got hurt," says Ritsu, eying me across the table.

"Ritsu…" starts Dad. "Someone could have gotten hurt. And you can't call what happened to the trees 'fine' either. You're smarter than that."

Mom is more troubled than she's letting on. She's throwing glances at the chatter where the families have gathered to eat together. We have set up our own table to have a private conversation. They're such good kids. It has to be something I did…

"Well, we can tell them what happened," suggests Ritsu half-heartedly. "It would be telling the truth."

Ritsu is very cute, so Shigeo has a hard time saying no to him. I suppose I have to talk to Ritsu later. Dad looks at me, and my eyes automatically swerve away. "What do you think, Shigeo? Do you think things are fine, too?"

Ritsu is practically shaking in trying to keep his mouth shut. How unfair! Nii-san doesn't deserve this!

I did though. While we were laughing to the point of tears, our parents are blaming anyone but me. Their words are stricter than their actual thoughts. I feel the coils in my stomachheavy as stones. I'm taking advantage of their kindness. I'm causing trouble again. Why do I keep forgetting?

"No. Ritsu and I were wrong. I'm sorry, Mom, Dad. I… I know I should be better." Even without hearing Ritsu's thoughts, I can tell his shock at my admission. He hangs his head, mumbling an apology, too.

"Nii-san wasn't going to do it, but I goaded him. Please don't be too harsh on him…" says Ritsu quietly. His eyes turn further away. "I just wanted him to have fun."

It's my fault, I wanted to tell Ritsu. I shouldn't have went along. It's not Ritsu who should be my keeper.

But what Ritsu said is enough to make our parents conflicted. They're thinking about the same thing.

It's because I'm psychic. The moment I was born with pink hair on my head, I could move objects and read people's minds. I bite my lips, listening intently to the physical noises of talk and cackling fire amplified by my hearing aids.

Finally, Dad speaks up, reluctant at first. "There are… other ways to have fun. You kids need to be patient! Next week, we'll go fishing. Who was it who caught the biggest fish last time? It was Ritsu, wasn't it?"

Ritsu and I exchange glances. He offers me a small smile. "Nii-san did, but an octopus boarded the boat and stole it, so it was my win by default."

"Shige likes being out in the sea, dear," says Mom to Dad. "What was it again… Ah! Shige's telepathy range is 6 miles. If we get far enough, he won't hear too many thoughts."

"It's 9 kilometers now, Mom. It used to be 7 but it's gotten stronger," corrects Ritsu, sighing at the deja vu.

Mom frowns, touching her lips. "I remember writing 6 miles."

"It was 7. Anyway, it's 9 now. Nii-san hears half the size of Shinjuku now."

Mom gasps in disbelief. "No way. I'm sure it's 6. Maybe 6.5?" She turns to Dad for support. "You remember, don't you?"

"Erm…"

Ritsu dips his face into his hands, groaning.

Mom sets her sun straw hat on her lap. "Is going on another trip really okay?"

"Don't worry, my superior is very understanding," answers Dad after drinking from a bottle of water. "Money won't be a problem, though we might want to ask them to wait the next time they get into honors again."

Mom regards him with worry. "Take care of your health. They're smart boys. They'll understand."

"I know." Dad wipes the sweat on his forehead with a towel. "They're always working so hard. It makes me want to work harder. I can't let them beat me after all."

Mom looks on at Ritsu and I playing volleyball by the deck. "I wonder what we can do to keep them occupied. School might be too easy for them. I'm worried they'll get into more serious trouble and keep us in the dark."

"Like getting into fights?"

"It has happened before," says Mom, entwining her hands anxiously.

"Then…even more reason it won't happen. They've learned their lesson," insists Dad despite the doubt in his own voice. "Honor students don't become delinquents."

I remember something. Even though I explicitly told my parents that even the things they say out loud also form thoughts in their heads, they have a habit of forgetting the technicalities of my powers. There's something I should tell Ritsu.