The Sage

The K'Thonim known as "The Sage" is a bodyless being that came to this plane over 3500 years ago before The Great Darkening. His real name is Sagg'Itharnat, though even that is as close as auditory senses can achieve his name. He survived the Great Darkening because he intentionally blew out The Plekenergia stations around him, saving what he could of the disaster.
He watched from his vantage point as a disembodied creature over the last 3500 years as the technological marvel that his species created to mine the T'Shole was wrecked by tiny mortals of this world. He watched as the mortals of Europa hunted down any traces of the K'Thonim, even further reducing their influence, but by this time he was more concerned with doing what he could on this side of the Great Western Ocean.
He resents being cut off from his home dimension and what the little tiny mortals have done to his species. He's not really concerned about home, and he worries that if he goes back he will find just as bad a disaster there, so he is satisfied with that he has made for himself here. He is motivated by a certain vindictiveness toward those mortals from the Europa region. He finds them arrogant and grows angry that they dare come across the ocean to spread their "disease" of independence to his own home turf.
The Sage enjoys a nice chunk of territory set aside from the other K'Thonim that survived. His influence runs from the east of Boriken down the island chain into the southern reaches of Atlantica and onto the mainland there. He also enjoys thorough control of the Harionak communicating with them through his subverted witches and temples that survived. He still has his followers harvest T'shole, though their techniques are primitive compared to what he had in the hayday of the K'Thonim.  He is intentionally driving the Harionak north against the Taino because he benefits from the T'Shole they harvest for him when he is at war.
Players that become aware of The Sage as an entity cannot kill him directly, but they can make war on his resources (temples, artifacts, and the Harionak) until he can't do much against them.  This would be a long campaign, and killing a K'Thonim is not a simple thing, and much more akin to killing an idea.

Divine Domains

The Sage is not divine, and instead influences the world through his dark witches

Divine Symbols & Sigils

He likes to use the shark as part of the ethos he uses with his followers.  They currently think of it as his symbol

"We know that the Harionak have named the K'Thonim that they follow 'The Sage' and they make sacrifices to him and feed him that way.  We are aggressive about defending ourselves against them.  There are those of us that are starting to think that perhaps The Sage benefits from this perpetual warfare somehow.  Getting the chiefs to fight a more expensive war than the skirmishes we are already fighting is far too difficult."
~High Druid Alto Beyat of Boriken