Okkoto is an old boar god whom had been blinded for reasons unknown. Not much is known about Okkoto's relation to Nago, but as seen by the movie he is as influential a leader as his predecessor Nago had been. During the storyline, he was first visibly seen leading his tribe through the forest towards Iron Town.
He first meets Ashitaka whilst he is with the Wolf clan in the Great Forest, it is there where it is revealed that the old boar is blind. Okkoto is told of Nago's demise and the grotesque form he had taken by Ashitaka and thanks him to the dismay of his followers. Okkoto thereafter demands that Ashitaka leave the forest otherwise the next time they meet would be the exiled princes death.
After the battle of Iron Town, Okkoto is found to being gravely wounded, Mononoke does her best to guide the blinded boar lord through the forest, it was at this point that Okkoto much like Nago falls prey to hatred and soon becomes the very same demon which his predecessor had also become.
Okkoto's rage comes to a halt when he is "kissed" by the Spirit of the Forest.