Name: unknown
He is the embodiment of Kaneki's Demonic power.
Kaneki's Demon half has its own personality and it's own goals.
The goal being "becoming one" with Kaneki, it is unknown what he means by that.
When he took shape, his looks are similar to Kaneki in many ways with only a few visual differences.
Those difference's being, his hair having a white color and is shorter than Kaneki's long hair (you could say he has a bob cut) his eyes are blue, he has sharp jagged teeth.
Since he is the Demon half of Kaneki, he possesses 4 horns coming out right above his ears, 2 wings on his back right around his waist line and a lizard like tail with 4 Thagomizer at the end of his tail similar to a stegosaurus.
Likes and dislikes: exactly the same likes and dislikes as Kaneki.
When Kaneki sealed his memories in his heart, he wasn't able to see the face's of Shino, Yuuka and Miku but his Demon half did see their faces.
And he knows how hurt they were.
Since then he tried numerous times to convince him but he wasn't heard by Kaneki or what the Demon half calls "fragments" of Kaneki up until recently.
Normally the Demon half of any Half Human Half Demon would be a bit more evil than their human half.
But for Kaneki and His Demon half there is no trace of evil within both of them at all.
The Demon half hates violence and hates hurting people (As seen in the chapter where he first interacted with Millie) and most of all bad people.
He knows things Kaneki doesn't know like how the girls feels for Kaneki.
Lastly, he considers Kaneki and Himself as the same being because he cares about himself despite being literally hated by himself. Still he is willing to help his Human half (Kaneki) in any way, shape or form until they can become "one".