Not a specific or an important character(s). Coral is what makes up the coral reefs in all of the shark wars reefs. Grey's old Shiver was called the Coral Shiver. In the real world they provide home for many fish, such as angalfish, grouper (Iarge fish, top of food chain, even eats some sharks), and much more reef dwellers. As you can see to the picture to the right, coral is what starts it all.