I'll choose Pokemon Trainer and he'll have 4 pokemon (aka characters) to choose from. If there happen to be any repeats, go for the nicknames I guess. So it's four in one character if that makes sense? I was thinking of putting in a Mega Evolution mechanic that could sometimes activate a special effect of some kind, but let me know if that (or anything I've got for that matter) isn't allowed.
To keep with the whole limitation on megaforms, only one megaform can be activated a day.
Mewtwo (Psychic God)
-Disable-immobilizes opponent for one turn
-Psychic (lowers defense by one stage occasionally)-25%
-Close Combat - 15% <----haven't used yet, but since Mewtwo actually can't learn it, changing it to Power-Up Punch
-Ice Beam (freezes opponent for two or three turns)-20%
-Mewtwonite X (when activated, transforms into Mega Mewtwo X and all moves go to 30% damage and lower opponent's defense by one stage in addition to their previous effect)
Charizard (Blaze)
-Fire Blast(causes burn damage that takes 5% each turn)-20%
-Fly (can dodge attack for one turn, but strikes on the second)-15%
-Outrage (must be used 2 or 3 times in a row at least, has to switch out afterwards so that confusion doesn't have to be taken into account here; exception to switch out rule is if in Mega form)-20%
-Fire Spin(causes burn damage of 2% each turn)-foe is trapped and is unable to move.
-Charizardite X (when activated, transforms into Mega Charizard X and all moves go to 30% damage and lower opponent's attack by one stage)
Lucario (Blue Ninja)
-Aura Sphere- unavoidable 20%
-Dragon Pulse (draconic enemies of any kind take double damage)-13%
-Bullet Punch-20% (and is able to go through multiple enemies with the 20% each)
-Double Team- avoids damage and returns the damage it was about to take if successful.
-Lucarionite (when activated, transforms into Mega Lucario, and all moves, with exception of Double Team, increase 5% percentage in power each time used while in mega form. Also, every two turns it has the opportunity to attack twice.)
(to be updated with last pokemon)