In Pokemon Platinum who is the 6th gym leader?

Answer 1

After you beat the 5th gym leader (Crasher Wake) he will grant you the power to use Surf outside of battle. Fly to Jublife City and exit towards the left. Surf left ways along the water you find until you reach Canalave City. (I recommend repels) In this city you have the Steel-type using gym leader Bryon. Use a good Fire-type.

Answer 2

Byron uses Steel-type Pokémon in his battles. Trainers who defeat him will receive the Mine Badge, TM91 (Flash Cannon), and will be able to use Strength outside of battle. Byron asked Riley to become a Gym Leader, but Riley declined because he thought Byron's son Roark should be considered first. Byron isn't surprised to find his inexperienced son lost to the protagonist, but is enthusiastic about the next generation of Pokémon trainers. Byron resolves to train harder at Iron Island to compete with younger trainers. He apparently owns the normally deserted cabin on Iron Island. After the Elite Four, he can be found there. Speaking to him results in him chiding himself for still treating Roark like a child, then he'll give the player a Metal Coat and leave. In Platinum, he mentions that he lived on Iron Island for a long time and so feels out of place when visiting the Villa. Along with those visits, he can also be battled again at the Battleground in Platinum.

Canalave Gym * Before battle : "Ah! That's Oreburgh Gym Badge! I see, I see! You've defeated my son. But that's no surprise. He still has much to learn. In place of my son Roark, I, Byron, will take your challenge!" * After sending out last Pokémon : "Oh, what's this? My last one! This is where we make our stand!" * During battle : "We're not done yet! There's no giving up!" * When defeated : "Hmm! My sturdy Pokémon, defeated!" * After being defeated : "You were strong enough to take down my prized team of Pokémon. In recognition of that power, I give you this: the Mine Badge!" : "Gwahahahaha! The Sinnoh region is vast! Tough Trainers like you and crop up constantly to challenge the old guard! With more young Trainers like my son and you two taking charge, the future of Pokémon is bright! But I'm not stepping aside just yet! I merely need to rededicate myself to training on Iron Island."Villa : "Guhahahaha! How's your Villa? Can you give me a tour?" : "Gwahahahaha! I spent a long time living on Iron Island. A place this fancy, I feel a little out of place. Don't get me wrong, it's a great place. It's nothing like my son's!" : "You're acquainted with a fellow named Riley, aren't you? He's a mystifying sort, that one. I have no idea how old he is, to tell you the truth."