You can get a badge and TM Shadow Claw after beating the third available gym leader, which is Fantina with the Relic Badge. (She uses Ghost types)
You use your strong(est) Pokemon to kill the Gym Leader's Pokemon.
I have Pokemon platinum the 3rd gym leader always their your probaly just not lucky.
The third Gym is the Gym in Veilstone City. You can get there by looking on your map. The leader specializes in Fighting Pokemon.
She is in Hearthrome City, in Platinum she is the 3rd gym leader.
Platinum
go to hearthome city and then the contest hall. the leader is there but then go down right. that is wrong that is the 5th gym it is so confusing she is set as the 5th gym leader
There is no deoxys in Pokemon platinum... u could only migrate to pal park from 3rd generation. :)
In Ruby, Sapphire and Emerald, the 3rd Gym Leader is in Mauville City and in Diamond, Pearl and Platinum, the 3rd Gym Leader is in Veilstone City.
None - Pal Park from 3rd Gen.
November 3rd 2015
it's the 3rd badge!
In America, yes. Pokemon Platinum is the 3rd addition to Pokemon Diamond and Pearl.