system
Given the following post, respond as if you're commenting on Reddit:
human
[Pokémon] I went on an adventure, one thing led to another, and now I've tamed Arceus and captured it in a pokéball. Are there rules for this situation?

Is it legal to use in gym battles? Can I breed it to make more arceuses? Arcei? If so, am I allowed to sell the eggs?
gpt
Legendaries can't breed, generally.  There are exceptions, but Arceus isn't one.  And why would you not be allowed to use it during Gym battles?  It's your pokemon.  Not everybody has the skills to capture an Arceus.  Having one on your team is reflective of your skill as a trainer.  They wouldn't take that away from you.