I'm not sure why you would need this but i would go with Arcei. Kinda like plural for platypus is platypi.
There is not an arceus trophy, and arceus was created after brawl, so arceus is not in brawl
arceus
ARCEUS
Arceus has no gender.
Arceus.
arceus
Arceus.
no
Arceus is not avabile. Right now, hack or use cheats to get Arceus.
Arceus has never been distributed as an egg. If you are referring to the egg from the HeartGold/SoulSilver Arceus event, it hatches automatically.
arceus is the alpha Pokemon
Yes Arceus is legendary