Who is Aroooon from Deep Wizardry and what is their importance?

Aroooon is the Eldest Blue about the Gates. He is about one hundred and twenty feet in length from nose to tail, and he has a deep, sober sorrowful voice. Aroooon's eyes are the size of tennis balls, and they reveal great age and wisdom. His flukes are in tatters and his steering fins are scarred and punctured. Aroooon also has the stump of a broken harpoon protruding from far down on his tail, the wood is rotting and the metal being consumed by rust.

Arooon is selected to play the part of one of the Untouched in the Song of Twelve.