Well, He's in many places. The first place you can find him is in this cave in Davenport or something like that (Haven't played in some time).
The second place you find him in near 6th gym. He gives this machine to identify unseen Pokemon.
The third is at 7th gym. After defeating to 7th gym you find team magma re-awakening Groundon. And they try to take over the space shuttle building.
The fourth place is in Sootopolis Gym. You have to capture Raquaza in order to go in.
The last place is in Meteor falls. (Be aware that his Pokemon's is all lvls 70+) All steel its good to have lots of backup potions with u.
(According this to Pokemon Emerald)
Mossdip....
after you beat mossdeep gym talk to steven go to steven's house in moss deep town
You go to Steven's house in Mossdeep city. He's northwest of the Pokemon Center. When you enter, he'll give you HM08. HM08 (Dive) is exclusive to Pokemon Ruby and Sapphire and is obtainable in Mossdeep City from Steven who resides there. Steven
You have to find Steven and he'll give you Devon Scope and you use that on the invisible object.
you have to find steven get a Devon scope and use it on the invisible keckleon in front of the gym
Mossdip....
steven? or scott? since steven is the champion
you cant beat steven in pokemon soul silver only in emerald,ruby and sapphire
in a house
Ash
Steven gives it to you in his home in mossdeep city.
In Pokemon Sapphire, Steven is the Champion. If you want to find him, beat the Elite Four. In the next room he'll be waiting ready to battle you.
No, you only battle Steven because in Pokemon emerald Wallace is the champion.
Steven gives it to you at his house in mossdeep city.
You go to Steven's house in Mossdeep City
metagross, armaldo, claydoll, skarmory, cradily, aggron.
Meteor Falls