The Sewer is a secret area, in The Park. It is an underground short-cut between, the River Bank and the Skate Park. Emperor Barodius and Kazarina used to be located here. Now they have been moved to Gundalian Ship .
How To
Go to the Skate Park in the Park Area , and go to where the tan wall has the pictures on it, and go in that little gap in between that wall and the fence.