How do you find Rood of the shadow triad on Pokemon Black and White?

Rood can be found in Route 18 on the beach near the body of water after defeating the Elite 4, N and Ghetsis and receiving the National Dex as well as the Super Rod.
Rood can be found in Route 18 on the beach near the body of water after defeating the Elite 4, N and Ghetsis and receiving the National Dex as well as the Super Rod.