The Arcanist

The Arcanist was once an ordinary grástiga - if any of them can be considered ordinary. Centuries ago, for reasons unknown to all but a few, the Arcanist was imprisoned in a tower on a hill, time sped up dramatically within to make it seem as though the world outside was passing at less than a crawl. He could not leave, and he could not fix the time dilation, but other than that the Arcanist had near limitless power within the confines of his tower.
Villagers regularly came to beg him for remedies and aid, and he typically obliged. Before the fall of Kena Lanu, even the king himself would come and seek consul from the Arcanist on the hill. All the Arcanist dreamed of was to roam and to explore the realms again, but he could only live vicariously through the stories he heard from others who came to visit.
When Med’aoulu arrived in Kena Lanu, he visited the Arcanist a single time. Neither have spoken much of it since, but the Arcanist once said to the Champions of Hardhaven

Oh, Med’aoulu? He’s a big softy. I know exactly how to deal with him.

Regardless, through messengers an accord was struck regarding the disposal of the raw Hatred at some point in the past, the Arcanist taking it in in large brass containers.
The Arcanist came to know the members of the Champions of Hardhaven. He took a shine to them, particularly Sunny, who chose to spend some time with the Arcanist in his prison of eternal time. After an encounter between Cear and Merkhal, the Arcanist was freed from his eternal torment. He shrunk his tower down and attached it to Sunny, journeying with the Champions until such a time when he was kidnapped away by one of his grástiga brothers. He has been missing ever since, though some divinations on Sunny's part have made it seem as though he yet lives.