They're not available during game play in White. Like all other Legendary or event Pokemon from past games they must be transferred over to White from their respective versions of the game.
(by a can of beans)The best Pokemon in Pokemon
Special event on spear pillar
darkrai and arcus
There is an event where you can get it from.
ho wont arcus give me celbi
I'm assuming that by "arcus" you mean "arceus". You can't get Arceus except from special events held by Nintendo, or by cheating and using Action Replay.
you have to trade it over from platinum because it is not in the unova pokedex
he can use all of the attcks cuz he is the god of Pokemon
An arcus is a medical term for a white band of cholesterol which forms at the edge of the cornea, or a meteorological term for a low horizontal cloud forming at the leading edge of thunderstorm outflow.
If you are looking for Arcues you need to trade it with either Diamond or Pearl Version.
No,arcus is not in mystery dungeon 1 or 2
If you mean What is the Latin for rainbow, it is arcus pluvius, or arcus alone, Arcus is a 4th declension noun, so its plural is not "arci" but arcus.