I know what to get off the games and get into the books.
the fifth gym on Pokemon diamond is the one in herthome city,
in canalave city
its for decoration
eterna city
Eterna City I think
Synshrone city is not a real city in Pokemon Diamond.
Blackthorne city is not in Pokemon Diamond but in Pokemon Heart Gold/Soul Silver
Fortree City is a location exclusive to Pokemon Ruby, Sapphire and Emerald. This means it is impossible to visit Fortree City on Pokemon Diamond.
The first gym in Pokemon diamond is in Oreburgh City
the fifth gym on Pokemon diamond is the one in herthome city,
south of hearthome city
Pastoria City.
its not in a city its on a route
There is no such thing as turtwig city
he is in Eterna city.
cancalave city
its in pastoria city