just give him the Pokemon he wants
Nothing happens you just trade him and he leaves and you go on with your Pokemon journey
steven has to be found in the museoum in peweter city an trade pokemon with him at saffron city
After you get your Hoenn starter and speak to Steven in the Pewter Museum, Steven will be in the Silph Co. bottom floor. He has a Beldum with a Dawn Stone to trade for a Forretress.
you get beldum.
Pewter museum!! :D
trade that steven dude for an evolved pineco
He does not appear anywhere else
After you trade with him he goes back to his own region to train and show the region the Pokemon but you never get to see him again.
He is in Silph Co. but you need to trade rotom over from Pokemon platinum
silph co to give you a hoen starter then he will still be there to trade Pokemon with you.
you can't trade with steven -_-
he doesn't show up in the game anymore except in the credits