yes you do
u could trade it from someone else or get it from an event
in stark mountain after natinal dex is obtained
Catch Arceus!!! 8 badges elite 4 National Dex/National Dex Upgrade Take down Giovanni at the eighth gym and then the Elite Four!
Arceus' number in the national pokedex is 493.
461
The last Pokemon on the national dex is Arceus.
get 60 in your pokedex and go to oaks lab
461
wifi/ internet connection
You can't catch Arceus. You can only catch Arceus in Pokemon Platinum.
get the nacinal dex and yhel be roming sinoh to get the natinal dex compleat the eleat 4 and see all 210 Pokemon and goand talke to profesor rowan and profesor oke will dash in to up graid it
heck no! you need natinal dex!