you dont find him, you get to a curtain point in the game, then he runs around the reagon. same with rouco. but, secoon always runs away. you trap him in the kanto reagon.
Chat with our AI personalities
After you've met them in Burned Tower they will roam freely in Johto. They'll appear in the grass randomly.
You can't find Mew in Pokémon Silver.
You can find sunkern in national park
Mt Silver.
Union Cave