Every so often I'm going to introduce a potential "unexpected" newcomer that I feel is on some level plausible. I'll try to focus on characters that rarely (if ever) get brought up. Between Sheik, Ice Climbers, Zero Suit Samus, and Pokémon Trainer, Sakurai likes to surprise us with unexpected characters who utilize unique fighting/transformation mechanics.
Why Eevee?
- Eevee is the main character's Pokémon in Pokémon Conquest
- Eevee is your rival's main Pokémon in Pokémon Yellow
- Eevee is the star of the upcoming short movie "Pikachu and Eevee Friends"
- There's a rumor going around that said movie will introduce a brand new evolution from the next generation
- Its evolutionary forms represent three generations of Pokémon games
When choosing Eevee on the character select screen, you must also select an evolutionary stone: Water Stone, Thunderstone, Fire Stone, Sun Shard (hidden), Moon Shard (hidden), Moss Rock (hidden), Ice Rock (hidden), or random. This determines which form Eevee can evolve into during the fight. If you don't like this idea, then perhaps the various stones can be "discovered" during gameplay while fighting as Eevee.
Obviously, Eevee is the slowest and weakest of all the forms, so you're going to want to evolve.
Attack the opponent to build up your level bar.
When your level bar maxes out, it will light up and pulsate. Use your Down Special Move to level up and trigger the short evolution cutscene.
While eight characters in one might seem like a lot, all "Eeveelutions" share the same core move set -- they are essentially Melee-style clones. Various attributes (speed, weight, power, etc.) differ between them, and certain attacks are imbued with unique properties; some of Jolteon's attacks might shock the enemy while Flareon's might burn them.