is the spiritual and temporal leader of the people of Series Eleven
His official title is "High Father of the Sept", and he is thousands of years old, having kept himself alive and well by occasionally consuming the souls of his subjects, which all belong to him by law.
He is tall and bulky, and has white hair and a white beard. He wears lion skins and many ornaments.
He is absolutely selfish, accustomed to doing whatever he wants.
It is said that he is responsible for keeping Series Eleven down to a single world, in order that he have no rivals.
See also The Lives of Christopher Chant (spoilers).
"He is considered the equivalent of Series Eleven's Chrestomanci, according to Chris Chant's words."
- No, what Christopher said was that Chrestomanci was the equivalent of the Dright, and he only said that so that the Dright would consider him worth talking to.
- There is no way that the Dright is really equivalent to Chrestomanci. If anything, they're opposites: the Dright's selfish use of magic to improve his own life at the expense of those less powerful is precisely the sort of thing Chrestomanci is pledged to fight.