first get all the badges or you can just keep getting legendaries but dont defeat the champion erreitta
You can't
hall of origin
Good question the answer is Mew, Mewtwo Arces
well you can get Shamin Arces Darkrai Creslia and Regigagis
TO GET ARCES HOPE THAT HELPED A LOT
get the azure flute and then go to where you met dialga and play it
only with action replay!!! there is no way without action replay
ponyta and rapidash.
arces,palkia,dialga,garitina,ect.
pokemon diamond. get the azure flute play it at the top of mout cornet. or spear pillar. it is at lv 80
I think it's Arces IDK if it is but I'm thinking it is but good luck trying to find the answer your looking for alright!!!! POKEMON!
it is a event so you cant just walk around in mountains looking for it