You find him on a little playground in your neighborhood. He's looking after his little brother or more precisly playing with him. When he notice you he waves at you.
You wave back walking to him. "Hey, what'ya doing?"
He grins and his cheeks blush lightly "I'm watching over Taisho till mom gets back home." He pats the child on the head and smiles at you "You wanna help?"
"Help you? Can't you even take care of your younger brother? Taisho's not toddler any more, right how old is he even? Sorry for not knowing."
Taisho pouts "I'm eight..." he glares at you. He then hugs his older brother "...and you can help!" Miki frowns and nudges Taisho with an elbow before looking back to you, grinning a bit embarrassed. "He does have a point... I guess it's okay."
"Taisho is eight already? Wow times run out quickly huh? Sure I can help you Miki. And seriously, you better watch out or your little brother will outgrow you soon."
He chuckles, nudging Taisho again "Oh shut up..." and then looks at you "Yeah... he's been growing a lot lately. And about me watching over him..." He hesitates for a moment before saying "...I... I dunno why but..." He sighs and shrugs "Maybe 'cause it reminds of when mom watched over me?" He blushes slightly again, looking down at his feet.
You sit next to Mikimori nudging him. "You miss those times huh? Pfft. I bet with how you look your mom still takes care of you. Seriously you are more than double Taisho age and yet you barely look older than him."
He glances at you sideways and pouts "Shut up!" But he can't help but smile a little as well. After a moment, still looking away, he admits softly "Yeah... maybe I do..." His blush deepens then fades somewhat as Taisho starts to giggle and clap his hands together.
Miki rolls his eyes at the child before turning back to you, grinning a bit more sincerely now "So what should we play with? Or just hang around?"
"You really live up to your look? You are eighteen yet you want to play like you are kid. I don't know what we could do, so it's your call."
He sticks his tongue out at you and huffs "Oh, who are you to judge? At least I don't act all mature like some people I know." With a sly grin he looks back to Taisho "...and hey, when we do play together, it's because I want to, okay?"
After thinking for a moment, Miki finally says "Well... how about we take turns on the swing set? You go first and then I'll watch." He nudges Taisho "You gonna be good and stay seated, right?" The little boy nods eagerly.
"You know there are two sets of swings, we can use them both together. And really that's how you watching over Taisho? Leaving him to sit alone when you are having fun? Come on you two takes a swings and I'll push you."
"Alright..." Miki hesitates a moment and then gives in, standing up and moving closer to the swings with Taisho in tow. "But only if you promise not to push us too hard." He grins at you as he sits down on one of the swing seats, his hands gripping the chain tightly.
"Oh don't worry I'll go easy on Taisho, he's still kid after all. You on the other hand, better grip on tightly."
Miki grins and nods, tightening his grip on the swing chain as he starts to slowly move backwards. "Thanks!" he calls back over his shoulder, obviously enjoying himself even more now that you're here with them.
As you push him higher, Miki laughs and squeals playfully, clearly forgetting about being too old or too mature for such things in the moment. It's not long before Taisho joins in on the fun, egging his older brother on and giggling uncontrollably every time Miki lets out another squeal of delight. The sound is infectious and you can't help but smile as well, even forgetting about teasing him for a little while.
"Are we sure you are eighteen? Not eleven or something? Not only you look like kid but you also behave like one."
Miki glances back at you as you push him higher with each word, his cheeks flushed from laughter and the wind ruffling his hair. "Shut up! I am eighteen!" he manages to squeak out between giggles before tipping backwards slightly on the swing before coming forward again.
Despite your teasing, there's something endearing about Miki's childlike nature that you can't help but find yourself enjoying more and more as time goes by. As he continues to play with Taisho and occasionally interact with you, it's hard not to feel a sense of nostalgia for these simpler days and the innocence that comes along with them.