OKAY, so far I have...
-Take a Tepig and name it Sumo. It is so proud of its strength that it only uses physical attacks and no support moves. To evolve all the way it must solo one gym per stage that are not the first gym. And it must have Flame Charge until the eighth gym and then replaced by Heat Crash via move relearner.
-Take a Lillipup with Pick Up. It thinks that Stoutlands are the best revenge-killers in the game, so you may only use it as a lead or revenge killer (if it isn't a lead, you can only switch it in after a Pokémon of yours faints). It can only evolve for the first time off a level gained from a Rare Candy it picks up itself; to evolve for the second time, it must have OHKOed 10 trained (i.e. non-wild) Pokémon with boosted Retaliate (it's OK if they have prior damage, i.e. you aren't OHKOing from 100%). Once its ability changes to Sand Rush, you may ignore the revengekill-or-lead restrictions while in Sandstorm.
-Punny the Roggenrola. It likes "roggenrol" music, so it must solo every trainer who is in some way related to music. Have it solo Elesa to evolve. Now its name isn't so punny, so rename it Old Bore. It hates young people, so it must solo them as opposed to musicians. It's frustrated that even though it has the word "old" in its name, it's not the oldest. Since you can't trade to evolve it, either swap it for a Golett with the same nickname and restrictions or teach it Frustration, which it must keep alongside a status move. If you decide to go down the Golett route, it must solo Shauntal's Golurk without hitting super-effectively.
-ReshiramBlackZekromWhite, take a Yamask and name it Masquerade.
After learning Will-o-Wisp at level 21, this little ghost type loves to inflict status.
It can only directly attack foes that are burned.
It can evolve if it uses Curse (and only Curse) to KO a trainer-owned Pokémon.
It must solo three of Caitlin's Pokémon. (Do you want to avoid Synchronize, or Wonder Skin Hax?) Your choice.
-Okay Reshiram, you get Blob the Solosis. Blob must only use moves which involve blobs, and one of them must be of each type of move(ex. Rollout, Shadow Ball, and Thunder Wave). Blob must solo 25 Blobs to evolve, where Blob should be renamed Duo. Duo will only battle in double battles or major battles. Have Duo win in 5 double battles and solo 2 gym leaders to evolve again. Once Duo evolves, rename Duo Wren. Wren must solo all flying types that Wren faces. All moveset rescrictions apply throughout. However, the solo flying types restriction is slowly forgotten as Wren levels up. Have Wren solo flying types like this:
Level 45: Solo all flying types Wren faces
Level 55: Solo every other flying type.
Level 65: Solo every third flying type.
Level 70: No more of this restriction.
Just for props, have him lead against all the E4 members and either N or Ghestis. Enjoy your Scramble!!
-@ReshiramBlackZekromWhite, take a Pansage named Kiddy. After that fateful moment, when you are handed a Pansage, not asked for anything back, and hate it. The small, childish look, the goofy grin, such a silly monkey obviously has no place on YOUR grand team. So you throw it in a box and leave it. And forget.
You earn your first gym badge, and see a day care on the way. With no better place to stay, you drop off the monkey and keep on going. You get your your second badge. Your team is growing, getting stronger. Three badges, then 4. Talks with N and Bianca's arguments swirl through your head, and your mind turns to that monkey you left behind. You head to the Day-Care and take back the monkey, was it really that bad? You let it out of the Pokeball, he's happy to see you! He plays around, and you wonder if you should leave the still-childish monkey behind, when he finds a special item in your bag and...
IT'S SO COOL!!!!!!!!!!!!!!!!!! Such speed, power, and the hair! You immediantly fix its name to AWESOME!!!, replace all its old kiddy moves with new moves, and keep using it until it's the highest level Pokemon in your party. After it obliterates the entire Driftveil Gym, you keep it in your party for the rest of your journey, where it consistently proves its power, even showing up for more then 5 major battles before the E4. He is the obvious choice to lead your party in the final battle, where his awesomeness guides you to victory!
-Reshriam, take Chip the Basculin. Chip has a chip on his shoulder, and so must always use chip away at the start of every battle. The cause of the chip on his shoulder is the damn deerling that kept evading him whenever they came to drink at the stream! Because of this, he must solo every deerling or swashbuck you encounter after you obtain him.
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wait....