Birthday: 6th June, 1888
Height: 173 cm
Weight: 59 kg
William is the smart heir of the prestigious Twining family, that tumbles down because of his uncle.
He finds the true when the school year is over and he comes back home. The butler (and also his most royal friend) Kevin reveals to him that all the servants has gone away because of the Twinings now are poor, and he's the only one that decided to stay there, beside William.
William's goal is to become a power politician and a writer, but if no one can pay his school bill, he'll be obligated to leave the school.
So he need to starts to provide for his necessities by himslef and his first idea is to sell some high-priced antiques of the family, but it's there that his troubles begin.
Searching for them is the underword of the manson, accidentally he summons a demon with his blood, Dantalion, who reveals that William is heir apparent to Solomon, who has to choose who will become the king of Hell.
William is a rational person and he can't believe in demons, angels, and obviously, in God (this is the reason why he spents the hour of religion just sleeping in the church). So he doesn't choose Dantalion as king, he can't accept his existence!! Since his blood is awakened, William's life will be totally different from that moment, and all the kinds of devils will search for him, in order to be chosen as new Hell king.
William's life seems to be ruined, but he starts to live a troublesome school-life too, because Dantalion and Sytry, another demon, became his comrades in order to follow him and be chose as king.
William finds the way to explain all the strange
events and creatures that appear in fron of him, but he can't accept their existence as ones went from another world!
He considers true only things that can be explained with science and math, he's rational and realist.
Also, his schoolmate Isaac is involved in demons' world too, because he's keen about occultism and he always tries to summon a powerful demon, so William have to protect him too (obviously a simple human hasn't the power to control a demon).