Well, you just need high level pokemon, some full restores, and status healers. Or use the walk through walls AR code.
the best Pokemon for the Pokemon league is definetly latios
you beat the pokemon league and if youre talking about the one on victory road you have to get the national pokedex
In Pokemon League
beat the league and he will be gone
If you have a r4 with Pokemon diamond on it click on cheat y look walk anywhere then walk through all the walls
there are none that i know of in diamond. sorry(-_-)
I beat the league on Pokemon Diamond version, and there was no cave involved, if that's what you were asking.
near the Pokemon league
beat the Pokemon league
There is a road behind the Pokemon league where Shaymin can be found if you get Oak's letter.
She stays in the Pokemon League.
No