Pokemon Gyms and League
Since the dawns of History on Earth humans have captured and trained pokemons and used them to perform all sorts of tasks. Not only as living weapons of war, but also as tools of construction, medicine developers, food and raw material sources and countless other jobs that form several of the foundations of the civilization of Earth (the other ones consisting on the imaginative and powerful mind of humans). Some scholars theorize that every human has a latent psychic ability to enforce their will on others, which would explain how even young kids can enforce ancient beasts of wondrous power to do their bidding with enough training.
Thus, it's no suprise that a full culture has developed around the art of capturing and training pokemon. Groups of people that band togheter to practise and develop that art are known as Gyms. Each Gym usually has its own philosophies of how to best capture and train pokemon, many times specializing on a certain kind. Each Gym also has a leader, its strongest member that takes the role of main teacher and administrator. The smallest Gyms may be just a couple of a Master and Aprentice in some backwater village, while the biggest ones have dozens if not hundreds of members and luxurious installations in the peaks of mountains or the center of big cities. Gyms make a living out of providing specialized pokemon services, like Celadon City Grass Gym that produces all manner of beauty products, perfume, medicine, and if you are standing in good relationship with them, all manner of poisons. Or Saffron City Psychic Gym that makes great developments on the field of psionics, both human and pokemon. Or they may simply protect the local village of wild pokemon and hunt food. Either way, they usually get some kind of financial suport from the local government, including installations where to conduct their activities.
As the fastest way of making pokemon grow stronger and unlock new abilities is to make them fight, there's been implemented the Pokemon League as an incentive to make pokemon trainers fight each other. First one needs to defeat eight tier of Gyms, then to challenge the mighty Elite Four. With each tier defeated, the trainer receives a special badge that is both a sign of prestige and social status, and also offers acess to several special services and advantages. Trainers with several badges can outright ignore most laws, but if there's one unbreakable rule, it's that killing in the Pokemon League is strictly forbidden. All Pokemon Trainers are expected to know how to disable enemies whitout taking their lifes, and dead pokemons aren't good to anyone. Usually trainers themselves don't participate in the duel, altough that rule has been bended or outright ignored from time to time.
Defeated trainers are still expected to offer some kind of material reward to the winner. If they fail to do so, it's socially and politically acepted to take compensation.
Speaking of money, the government offers free, global healthcare to trainers and their pokemon in the form of pokemon centers, so they aren't afraid of risking their hide. If you find a trainer that got unlucky against wild pokemon but was left alive, you'll receive a nice cash reward for carrying them to the nearest pokemon center. Said reward is usually taken at the saved trainer's expenses.
Generally in any given region there will be eight Gyms directly sanctioned by the Pokemon League, each awarding a Badge tier. Even relatively weaker Gyms may give out badges, but no more than one sanctioned Gym badge will be found in any city/village. If there's more than one Gym, they compete in battle and the strongest one receives the right to give badges. Shame to the Gym that has to live under another Gym's shadow, even if they're tecnically stronger than a Gym in another city of the region. Either way, each Badge tier is linked to a progressively stronger power level, so that traveling trainers are expected to go trough a certain route, facing the Gyms in a particular order as they grow in power, and learning valuables experiences from each one. Sometimes they may spend years in each one before they can progress to the next, but the best trainers quickly learn everything a gym has to teach in a matter of weeks or even just some days.
Any trainer can try to challenge a gym, which involves first dueling trough the lower ranked members all the way to the Gym Leader. More exotic Gyms may include obstacles and puzzles along the way. Defeating the Gym Leader grants the badge, but doesn't exactly allow one to take his /her position. Again, being Gym Leader is not only about battling, but also about properly mentoring new trainers and developing and improving non-battle pokemon skills. Plus since each Gym is specialized in a certain style, one can always be cheap and bring pokemons to directly counter it. Either way, to replace a Gym leader one must show they can do a better job in all fields, which is usually a long and slow process to win the hearts and mind of the Gym members and other people connected to it.
Once all 8 badges of a region are gathered, one can challenge the Elite Four! This top group in the pokemon world is formed by previous Gym leaders that have proven their worth and valor beyond any doubt. They don't take disciples, at least not permanent ones, but may provide valuable lessons to trainers that took all 8 badges and then managed to personally impress them. The Elite Four divide their time between further developing their own training styles, settling disuptes between Gyms, and, when things get dire, taking themselves to the battlefield to save the day.
To reach the Elite Four, one usually needs to fight trough the other veteran pokemon trainers that gather nearby, eager for a chance to prove their worth and improve their skill. If one can fight past them, then they can ask for the ultimate sanctioned challenge, fighting the Elite Four members in a row with just a set of pokemon and brief pauses between each duel! If one wins, they're crowned Pokemon Champions and their names engraved in a special Hall of Fame. The title brings great popularity, chicks/boys depending on the trainer's preferences, offers for high-ranking jobs, but again, not a possibility of actually joining the Elite Four. That is reserved for veteran Gym Leaders that have not only proven combat prowess, but also a great understanding on how to properly train pokemons. Regardless, Pokemon Champions are still the stuff of legends, going then to take on new challenges, traveling to remote and mysterious regions to capture rare and elusive pokemons while saving the world.
Recently, between new advances on technology, psionics and the study of interdimensional gates, Gyms and the League have been expanding to other worlds. Altough for now its presence outside Earth is minimal at best, noticed as just a curiosity by the governments of those other worlds. But still enough to start atracting trainers of those new regions.
Government on Earth tries to show Humanity as an unified group, free of petty wars and squables inside the species, unified against the common threat of wild, rampaging pokemon. That's not necessarily true. Team Axe. Team Aqua. Team Magma. Team Galaxy. Team Chaos. It has been known by many names trough the ages, but they share the same basis: groups of trainers that would use the power of pokemon for terror and domination over their own brethern. If you feel wronged by society, if you're desesperate for quick money, if nobody else will help you, or if you just want to see the world burn, then Team Rocket has a place for you.
Stereotypical representation of a Team Rocket member.
Now the government usually dismisses Team Rocket as an unorganized group of loonies whose members could spend years stalking a newbie trainer kid and still fail to take even one of their pokemons. And it is indeed true that Team Rocket has pretty low recruiting standards and will basically take anyone who can throw a pokeball and order a pokemon around. But don't let yourself be fooled by its bottom members. Team Rocket is in truth an highly organized and very dangerous group. Even if it's true most of their members don't even carry weapons, a pokemon is much easier to carry past trough checkpoints, and just as deadly in the right hands. Team Rocket knows it has no chance in a direct fight against the military and Pokemon Gyms, so they usually act from the shadows and hidden bases, building up their power before striking. Their members are renowed for specializing in smaller, less flashy and/or poisonous pokemons that can get the job done with minimal ruckus.
If there's laws against it, then you can bet Team Rocket is looking for a way to exploit it trough pokemons. Death matches betting rings, highly addicting drugs extracted from pokemons, rare specimens kidnaping and trading, assassinations, secret technology steals, and even whole cities taken over for their raw materials, you can bet Team Rocket has an hand on it. Some aparently natural disasters are even blamed in Team Rocket employing more powerful pokemons. And more than one highly proeminent Gym Leader and politician has been revealed to be a Team Rocket member, advancing their agenda.
Rare footage of the pokemon underworld. The highly proeminent trainers and Gym leaders depicted on it denounced the photo as an elaborate fabrication and denied any involvment in such activities. Ironically enough, it's not entirely impossible that Team Rocket itself would've indeed fabricated such an image to mud the name of good people.
Team Rocket usually acts on independent cells, each with its own goals, many times taking other names depending on their purpose, but they answer all to a specific leader, which usually hides in the shadows and coordinates the cells as he sees fit. Even when aparently defeated, they usually simply go into hiding for years as they rebuild their strenght. Even if taken out of the picture somehow, they just open the path for a new talented leader. Even the Elite Four had to be called to deal with Team Rocket in certain ocasions. For this criminal group, the ends always justifies the means, and their ultimate end is power over everything they see.
With the recent advances on reaching other planes from Earth, Team Rocket has extended its cluthes to the new lands as well, seeking new exotic creatures to capture and exploit. Rumors are that they are extending their recruitment programs to those new areas.