Well after you beat the elite four you can fight him as many times as you want in the fight area. but sometimes he's not there so you have to wait. Be Careful though! He gets strong!
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I don't think the first answer is accurate..
Here are the conditions to battle your rival;
1. Beat E4
2. Help Buck at Stark Mountain
After you're done, Barry should be at the Fight Area. But he only appears if it's on a weekend (Sat/Sun) but you can change the date on your DS/DSi anyway, though.
You Have To beat Red First.
In the beginning of the game, he isn't there. Towards the end, you will find his rival on cinnabar island by himself. After you talk to the rival, he leaves to go back to viridian. Fight the cinnabar gym leader, go back to viridian and the gym leader should be there. The man you talk to on Cinnabar Island Isn't the gym leader, but his rival. After you speak with his rival on cinnabar, the gym leader reappears in viridian. You have to fight and beat the cinnabar gym leader first.
He is benevolent with a heart of gold. - She is beautiful and she has a heart of gold.
A heart of gold itself is an expression relating to someone kind. "They have a heart of gold".
To defeat your rival with a croconaw teach it ice punch, blizzard, and/or ice beam.
you don't
The seventh time around, you battle your rival at the Dragon's Den in a double battle with you and your rival against Lance, the Champion, and Clair, the eighth gym leader. View the Related Link for more information.
Gary isn't in heart gold and your rival chooses whatever Pokemon is opposite to yours.
He finds you throughout the game, just continue the story and forget about him, he is your rival, you will fight him at specific times in the game.
You Have To beat Red First.
he said work for me you little red head
your rival is giovanni's son on heart gold/soul silver
You beat the Pokemon league 56 times if that doesn't work i don't know what will
da carnivl, wario's gld min, and yr butt.
In the beginning of the game, he isn't there. Towards the end, you will find his rival on cinnabar island by himself. After you talk to the rival, he leaves to go back to viridian. Fight the cinnabar gym leader, go back to viridian and the gym leader should be there. The man you talk to on Cinnabar Island Isn't the gym leader, but his rival. After you speak with his rival on cinnabar, the gym leader reappears in viridian. You have to fight and beat the cinnabar gym leader first.
They don't, he is your rival throughout the whole game and if he wasn't present you would not have a rival.
Just inside the route 4 entrance to Mount Moon