You saw the title, u know what this means.

assigning Pokémon team(s) and backgrounds.

Ok so first thing first, I feel like Cross would come from sort of a Gladion/Lillie situation, with XGaster kind of playing the role of Lusamine. It just feels accurate. Though the same can kind of be said for Nightmare (Gladion?) and a somewhat quieter version Dream (Lillie?), so don't take anything I say here as 100% what I think 💀

Teams (imo):

• Cross
- Bewear
- Crobat
- Braviary
- Beartic
- Porygon-Z
- Type:Null/Silvally (or Zangoose/Gallade)

• Nightmare
- Honchcrow
- Hydreigon
- Cacturn
- Roserade
- Garchomp
- Type:Null/Silvally (or Noctowl/Braviary [Hisuian bc he's old])

• Dream
- Solrock
- Goodra [Hisuian bc he's also old]
- Ampharos
- Sylveon
- Blissey
- Gardevoir

• Killer
- Gliscor
- Weavile
- Zoroark
- Umbreon
- Vespiquen
- Skuntank

• Horror
- Steelix
- Mantine
- Probopass
- Clefable
- Froslass
- Avalugg

• Dust
- Mismagius
- Magnezone
- Greninja
- Luxray
- Dustox (SORRY)
- Rapidash [Galarian]

Not sure if I'll add more later, but just assume they're all around level 55/60 and have somewhat good stats (also go look at "The Pokémon AU no one asked for but I made anyway" on AO3. I can't remember the author's name rn but immense kudos to them, it's literally so good so far. 100/10.)