The twisted inorganic angel Rosiel, beloved of God, is the younger twin brother of Alexiel, he is obssessed with his twin sister and in his narcissistic haze, he will stop at nothing to bring about her awakening. He must have this crazed love reciprocated, to affirm that he is as beautiful as he believes himself to be. In the distant aether of the longpast he told Alexiel that he would eventually "change, and bade Alexiel to destroy him before this transformation took place. This "change" is basically that he would slowly lose his mind and regress in age. Over the ages his powers have changed as well and he thinks of his changed self as being vile,, ugly and unfathomable.

Long silvery hair with a touch of blue tints, stunning clear, crystal eyes, those pouting lips...the perfect image of androgyny. Yet, underneath this angelic guise is a twisted and tortured soul. One who is seemingly a narcissist, yet whose mind in toiling in self-hatred. He is not in love with himself, but with whom he used to be.

Now he moves forward with goals that seem so vague to the readers of Angel Sanctuary. He claims to want to regain his old body back by awakening Alexiel. Does he want her to simply create a new body for him, like she did all those years ago? Or does he wish to "fuse" with Alexiel and become the perfect being? But, perhaps it is neither of these...perhaps all he simply wants is an end. An end to the madness that has consumed him...to end the "hunger" he suffers from. He may just want his older sister to finally fulfill the promise she made so long ago...the promise to bring him peace. To bring him Death.

Out of the two of them, Rociel was the one to earn God's love, and for this Alexiel was jealous of him.  His beauty was well known in Heaven, but his power did not match up to Alexiel's, for he didn't have the strength to stand against her when she sealed him into the earth.  He was unsealed by Katan, who gained the energy for Rociel's awakening through the game "Angel Sanctuary".  Rociel has been slowly driven mad, and now exists for his sister to love him and to acknowledge that he is beautiful.  He ignored Katan's wishes to return to Heaven, due to the chaos Sevi was making, but Rociel instead remained on Assiah in order to search for Alexiel and awaken her current incarnation to his power.  Long before the story began, when Rociel and Alexiel had been together and Rociel sane, he had realized that his body had been deteriorating for yaers and his mind wouldn't hold out much longer.  He begged for Alexiel to kill him when his mind was gone, so that he could not swallow up the world in his hunger for power.  Alexiel was unable to kill him when the time came, for he cried out to her, demanding to know how she could kill her beloved brother, leaving doubt in her heart.  She instead sealed him away into the earth.  Since meeting Setsuna, Rociel has been constantly attacking him and the ones he loves, trying to awaken Alexiel.  Inside Rociel and Alexiel together is the key to the tower where Adam Kadamon hides, and so he steals Alexiel's body in order to accomplish his goal.  He alone destroys much of Gehenna, killing many demons, and also attacks Setsuna, killing Kira when he tried to protect his friend.  Rociel has been pulling everyone's strings, watching Sevi's moves, and always seems to know what's going to happen and how. As Sevi mentally falls apart, as Layla, after she is raped by Sandalphon, Rociel takes over Heaven with his troops. He uses Lucifer, his new weapon, to drive Layla further insane, and imprisons Metatron/Sandalphon, keeping them away from any living creature.
[**taken from 'What Rosiel Wants']