#tl;dr a skier slighted him once

[tvitr]

So...

How did Grusha get into Pokémon training anyway?

I don't think there's actually a canon reason in the game so fuck it, have my headcanon.

(Also consider this a part one because man oh man did this get long and unwieldy)

Tl;dr he actually has friends and they're the ones who got him into it. Kind of.

More specifically, he has a group of friends he goes snowboarding with. He's known all of them since his pre-pro days, basically since they were all children, and though none of them ever reached the same heights he did in terms of their own respective careers, they've all just... stuck by each other.

Naturally, following his accident and subsequent retirement, Grusha was obviously... a bit upset. He'd still venture out onto the slopes every day to at least get some form of social interaction, but it was clear that he just... wasn't himself. He was quiet, less enthusiastic, seemingly always lost inside his own thoughts, and most worryingly, no longer confident in his abilities. His friends obviously knew why he'd changed, but as a bunch of emotionally stunted jocks who probably thought they'd all catch The Gay if they ever so much as thought about talking about their feelings, none of them were really equipped to engage in any meaningful or deep conversation with him. Not now, at least.

So, they did the next best thing they could think of; buying him a Pokéball. "You're the only one out of all of us who doesn't have a Pokémon," they told him,

He dismissed their concerns, obviously, telling them that he was fine (he wasn't) and that they were overreacting (they weren't), that only middle aged people stuck in jobs they hate and don't exercise get depression (wrong, also foreshadowing). He appreciated the gesture, sure, but he definitely wasn't going to ever need a Pokéball as he had no intention of using it.

Plus he wasn't entirely on board with the idea of abducting and attempting to tame a random wild animal anyway.

He puts the Pokéball in his coat pocket and forgets about it eventually, until one day he's returning home from another listless day on the slopes when he notices a Cetoddle following him. It's cute, and he stops to play with and talk to it, but knows it'll probably either lose interest in him eventually, or will stop following him once he descends to a lower, warmer altitude.

But it doesn't.

It follows him all the way home.

It seems uncomfortable with the balmy Medali heat, though despite him reassuring it it's okay to leave, and that he'll be back out on the mountain tomorrow, it still follows him to his flat. Part of him wonders if it's even a wild Pokémon at all. Though he knows Cetoddle are an exceptionally curious and friendly species, he's never seen one venture this far down the mountain.

He lets it into his flat.

It perks up once it enters, possibly due to the cool tiled floor offering it some respite from the evening heat, though it still seems tired and worn out. Grusha then realises he doesn't have the slightest idea on how to take care of one of these things.

He spends most of the evening on his phone, browsing various forums and websites on Cetoddle care, all the while the Cetoddle in question dozes peacefully next to him. He strokes it with his free hand, eventually coming to the conclusion that so long as he brings it to the mountain each day to graze in its natural habitat, he should be fine to feed it whatever. He gets up to check the fridge.

He remembers the Pokéball.

Cetoddle looks up at him curiously as he finally pulls it out of his coat pocket. He fumbles with it, almost dropping it in fright as it opens and pulls Cetoddle inside. It twitches.

It clicks.

A bit more fumbling and he releases it again, quietly vowing to only use the Pokéball to transport his new pal to and from the mountain to avoid it overheating like it did earlier. Sure it might require him to rearrange some of his furniture to make it easier for Cetoddle to move around his flat, but he's still not sold on the idea of keeping it in its ball 24/7. Plus, it is extremely cute. It feels stupid to admit it, but his heart does feel a little lighter just by looking at its bright smile.

He names the Cetoddle Persik, as per family tradition. Persik accompanies him to the slopes the next day; he is of course, lightly ribbed by his co-boarders for finally giving in and catching a Pokémon (despite his insistence that Persik literally followed him home), but they quickly warm to their new teammate. Despite all of them having Pokémon, they rarely battle, preferring to let them roam or chase them as they carve their way down the mountain.

That is, until, one day.

Grusha didn't know where the group came from or what their damage was, but they were all on skis, which was enough to make him dislike them from the offset. Coupled with the fact said group on skis were hogging his group's favourite slope, and he could tell this wasn't going to end well.

The skiers challenge his group to a Pokémon battle, their apparent leader singling Grusha out for a one-on-one battle. He tries to explain that he's no battler, he doesn't even know what moves his Pokémon has, but it's to no avail.

Of course, he loses. Spectacularly.

He feels a strong pang of guilt as he recalls Persik into the safety of his Pokéball, though that guilt is quickly swept away by anger as the skier returns to his herd, gloating loudly that he'd just taken out the great Grusha Ibáñez with hilarious ease. Grusha has a good mind to bend down, pack a hard snowball and peg it straight up the back of the skier's stupid head.

But he doesn't.

Just as quickly as his guilt gave way to anger, his anger gives way to something else.

Determination.

For the first time since his retirement, he feels a familiar spark ignite deep within. It's the same spark that drove him for years back in his glory days, it's his drive, his passion, it's...

It's like his old life returning to him, just in a different form.

He heads straight to the nearest Pokémon Centre, first healing Persik and then stocking up on Pokéballs, potions, antifreeze, everything he assumes a rookie trainer will need. That skier seemed to know how to battle competently after all. He'd need a lot of practice if he wanted to have a hope in Hell's chance of beating him. As well as more Pokémon. He couldn't bring himself to battle with Persik again.

He throws himself head first into learning how to battle; gregariously reading every book, magazine and website he can find about Pokémon battling, studying different forms and techniques he can apply to his own developing style, how to use each Pokémon he's been able to catch and train so far to its full potential. Admittedly his team stays quite small, still in part due to his reservations about catching wild animals unless they seem like they want to be caught, however eventually his team expands to include a Cubchoo (Arbuz), Snom (Klubnika) and a Sneasel (Yezhevika). He trains them all relentlessly, and to eventual evolution (even shedding a few tears when Klubnika evolved that one frigid night), getting to a point where sparring with his fellow snowboarding pals is no longer satisfying. They'd agree with him as well; though obviously it's great to see Grusha finally enthusiastic about something again, there's only so much getting their asses kicked repeatedly that they can handle.

He decides it's finally time to track down that skier again.