This legendary animal changes its body color as it ages and are very deep divers?

Whales

Explanation:

Whales are known as mammals and are found in deep and larger waterbodies such as the ocean. They are great divers who can dive as far as 2,500meters in search of food for its survival.

Whales are also known to change color as they age. The color change is commonly from their grey color to white color. Some scientific study believe the color change is as a result of injuries sustained by action of humans which means the older the whales the more encounter it must have had with a human.

rain is the best answer