>>57235187aura cultivationfag with a side of story-must-stay-the-same mixed with trying to upstart the hero because they see themselves as the isekai MC. Not in a hostile way like "I'm better than you", but like "getting pointlessly involved in events" through "coincidences" that if the reader knows the OG story would be able to tell is subtly pointing towards a specific episode/manga chapter/game/etc
So side-Character would meditate and practice martial arts despite being clearly terrible at it, and would show limited nearly comic relief level "aura abilities" like making a match stick sized flame from their finger which they obsess over and show off all the time. Other people think its silly because even basic psychic trainees can do more. Overall they'd have game like strategies that come off weird or entirely extra, they have custom moves you wouldn't expect, and they are a bit "weird" to others, but overall just a nice example of a normal reader getting sucked into a story. His team is split between Smogon gimmick pokemon and Waifu bait, except for something stupid like a simple bidoof he can't bring himself to abandon after it attached itself to him and is more a mascot going against the idea of the character being a pure meta-tard.
Maybe a chapter way down the line when it's pretty obvious to reader by that point, but not the in story characters, where he gets drunk and confesses everything about being isekai and wanting to do "X" now that he's here. X can be anything from normal stuff to 'fuck a lopunny'.
So overall a character who embodies many tropes and memes about isekai and going to other worlds, a character who wants to do great things and be a main character to his own grand adventure story, but also constantly showing counter examples of him going against "what's best" to do "what's right" and adjust to be less eccentric as the honeymoon phase ends. A normal person realizing why everyone in the pokemon world isn't 'slaying the heavens'