How do you find the fourth gym leader in Pokemon diamond?

Answer 1

The fourth gym leader is Wake in Pastoria City .
go south of veilstone
Find the galactic grunt in Pastoria city. Then, talk to him and follow him around until he decides to battle you and you win (he is seriously easy to beat). Then keep haeding north and talk to Cynthia, she will give you a secretpotion. Use it on the group of psyduck above solaceon town.You now have access to Celestic town! Go there and talk to Cynthia's grandmother. She is right in the middle of town, you can't miss her. She will talk about a galactic grunt threatening to blow up the town with a galactic bomb. From there, head of few steps north and battle the galactic grunt (he is also easy to defeat).go inside the cave he was blocking and examine the painting. Then Cynthia's grandmother will come in and give you the Hm surf. Fly back to hearthome city and battle the Gym leader. I suggest using a dark, ghost, or psychic Pokemon.You can also use floatzel or luxio/luxray, since they learn crunch, which easily beats all of her Pokemon in 1 or 2 hits.