Where is the Poké mon Jingcan Diamond Dragon King?

In non-thunderstorm weather, there will be a fixed-point sea thorn dragon in the honeycomb sea.

In any weather, there is a chance to find Mohammed of Lei Ming on the outlying islands. Of course, these two can also be met in super-large group battles.

The scales of dragons needed for evolution can be synthesized by robots in the martial arts school, and a more detailed synthesis scheme can be found in Poké mon Encyclopedia.