Noya Hienma

Noya「ノ夜, lit. Of night」is a high ranked possession-type demon of the Black Demon Series. He forms a contract with Guren Ichinose in Seraph of the End: Guren Ichinose: Catastrophe at Sixteen and becomes his weapon.

Appearance
Noya is described as a beautiful 12-year-old boy with milk-white skin, scarlet hair and eyes that match, and a pair of horns sprouting from his hair.

Personality
He is playful and mocking such as repeatedly calling Guren "cute" and takes joy in tempting him with desire and power. He also teases Guren with a countdown and says that he will become a demon soon enough anyway.

History
According to Noya, he was once a human before becoming a vampire that has lived for so long that he had lost track. At some point, Noya turned into a demon and got sealed into a weapon as part of the cursed gear development.

Book 3
Guren finds a demon sword at the end of a road which was thrust into the ground next to a running motorcycle. Desperate to become powerful to save his friends, Guren grasps the sword and loses consciousness.

Book 4
Guren hears a voice calling his name and awakens in a completely white space in his heart. The demon Noya tempts him with power and approaches him. He chats about Mahiru and says that Guren will turn into a demon regardless of whether he accepts that power or not. Guren touches Noya and willingly gives up his humanity, leading Noya to mock him for making the wrong choice. He says it is unacceptable for a human to give up on his humanity while he is still human. Everything goes black, and power overwhelms him.

Guren wakes up with the sword in his and a motorcycle next to him. He hears war going on all around him but no longer feels any pity or empathy. His desires encourage him only to kill, and he mutters about needing a sheath to suppress the demon's will before getting onto the motorcycle.

Although he loses control after killing all of the Thousand Nights members in the school, Kureto was able to restrain the demon and his squad saves him. After the restraints are put on Noya, Guren continues to use him in many battles, and eventually asks Noya to become his friend.

Book 6
Near the end of the book, Guren can unleash approximately 30% of Noya's power while maintaining control.

Book 7
Guren uses Noya by slashing the minivan his friends were staying in to help his friends draw their own demons as he kills the enemies that were after them. Noya speaks to Guren to fully accept him seeing it would be the final battle after Guren uses the demon's power, Noya tries to tempt Guren mentioning if he can catch up to Mahiru, seeing how Guren determination to use him to protect his friends he laughs and giving him more power. He tells Guren to kill all the enemies and lose control making Guren wonders if he should let his desire run wild.

After killing many enemies, Noya suddenly speaks to Guren telling him to dismiss all his feelings and emotions to become strong and gain strength to protect something and someone but Guren ignores him. When Kureto arrives and attacks Guren, Noya tells him if he can kill him but Guren ignores him. Noya wanting to know which is stronger Kureto's demon or him and Guren tells him that he just surrenders but Noya interrupts him still wanting who's stronger. After watching Raimeiki accelerates Kureto's body fearing he might be overpowered, Noya envelopes Guren with his curse strengthening Guren's body as Noya laughs at this thrill making him on par with Kureto, as Guren takes more power from the demon who almost goes out of control, Guren stops Noya on his madness and surrenders afterwards he uses Noya to cut off Kureto's arm.

In the final battle against Mahiru he uses Noya effectively and after watching Mahiru torturing Shinya telling Noya to give him the power to save him, Noya telling him to accept him to save him yet after receiving enough power the latter was too late but Noya takes advantage of Guren negative emotions and loses control by Noya consumption on verge of becoming a demon though a dying Shinya manged for him to regain his senses.

Knowing he can't defeat Mahiru he threw away Noya. Mahiru picked it up, welcoming it and stabbed herself in the heart using Noya and integrated with the demon into her heart, the curse spread all over Mahiru telling him the demon Noya itself was part of her plan. As her body was being dragged to Noya, much to Guren and Noya confusion telling Guren Mahiru's fate of becoming a demon, Noya tells him to become a demon instead. Noya's fate became unknown when Guren tried to talk to him.

Book 1
Unbeknownst to him, Mahiru and Noya actually incorporated with Mahiru plan, thus created his current demon Mahiru-no-yo. Leaving him confused each time he draws his sword,

Forms and Abilities

 * Demon's Thrall: Noya can enter it host's dreams and memories to create nightmares and break his host's will in order to take over his body.
 * Basic Form: Noya takes the form of a black katana.
 * Possession: Noya possesses his host to grant him immense strength and power as well as enhanced healing and senses while filling him with desires. The more desire his host has, the greater his power becomes.

Trivia

 * Noya「ノ夜, lit means Of Night and after Mahiru been absorbed by Noya curse, transforming into Mahiru-no-yo 「真昼ノ夜 lit which means Midday's Night both share the Night meaning this is probably because of the similar names.
 * Because of him turning into Mahiru-no-yo it gained all the powers and abilities that Noya originally had.
 * Noya mistakenly thought Raimeiki as a male demon not knowing the demon is a female despite both of them are demons.
 * Much like Yuichiro Hyakuya asked Asuramaru to become friends, Guren likewise did the same.
 * Noya is a very powerful demon even after seals and restraints were put on him as Guren was able to fight very efficiently using him in many battles.

Book 4
"Hello, Guren."—To Guren, Chapter 1 The demon took a step forward. Inky blackness spread beneath his foot. "…" As the blackness spread, Guren had the sense that something precious in him had disappeared.—To Guren, Chapter 1 Guren felt the words’ seductive pull.—To Guren, Chapter 1 Guren’s eyes widened in surprise. But it was too late. Blackness. Everything went dark. And relentless power surged into his soul.—To Guren, Chapter 1
 * A voice spoke in the darkness.
 * "'Hijack' makes it sound like I’m doing something wrong. I’m here because you wanted me, Guren."—To Guren, Chapter 1
 * "It makes me very happy that you want me," the demon said, smiling. "You desire power, don’t you? You couldn’t have chosen better than me ♪ Once we get inside each other, you’ll be stronger than you could have ever imagined."
 * "Oh? But we’re going to be so close. We’re going to be together for the rest of our lives. You should say my name, too. It’s Noya. Go on, say it. Speak my name, and I’ll give you a night of overwhelming carnal pleasure."—To Guren, Chapter 1
 * "Guren," he said. "Look at me. Look at how close I am. But I want the last inch to come from you, Guren… Want me, Guren. Hold me. Give your mind and body over to me. Then… you’ll be able to protect them all." The demon smiled sardonically.
 * "Well? Are you just going to run away again? Say that you’re not prepared to make your move yet? That the timing isn’t right? I like humans who’re like that, too. The kind who can run away shamelessly when it’s their own skin on the line. But you’re different, aren’t you, Guren? I already heard that you were different."—To Guren, Chapter 1
 * "You’re just so lost, and gentle, and weak, that it’s hard not to love you. Once we join together, our strength will be unstoppable! …There’s no need for us to hurry, though. It will happen sooner or later. You’ll become a demon. Even if you don’t touch me today, you’ll reach out for me eventually… They’ll all be killed, because you weren’t able to protect them… And then you’ll turn into a demon out of absolute despair. That suits me fine. Either way, it’s too late to stop. You can’t help but turn into a demon. We’re already intertwined."—To Guren, Chapter 1
 * "Aha, Guren!" Noya shouted in rapture. "Wrong choice ♪ You’d think it would be obvious, but humans should never give up their humanity? You really didn’t know that? You’re so adorable!"
 * "--Next, let’s save Mito, Noya said. What will you do if they’ve raped her? I bet it would feel good to punish the rapists? How about if she’s been killed? I bet it would feel good to avenge her. There’s so much fun to be had in the human world! I can’t wait until you and I are one, and I can finally be set loose!"—To Guren, Chapter 2
 * "Really?  But I thought you were the loner.  I mean, you’ve never believed in anyone.  That’s why you sought me out.  Because no one else would help you."—To Guren, Chapter 4

Book 5
"Once, I was a human. "Once, I was a vampire. "And now, I am a demon. "What do you suppose I’ll become next? "What will I gain by causing you to fall and transform into a demon? "That’s what you want to know. Isn’t it? You’re in a pickle now. All out of clues. If you’re ever going to find Mahiru, you should probably listen to what I have to say. Don’t you think?"—To Guren, Chapter 5
 * "Don’t, Guren. I don’t want you touching any other demons… You belong to me. There’s no reason for you to mess with other demons."—To Guren, Chapter 3
 * "Don’t judge a book by its cover. Demons appear in their most pure, undiluted form, from when their desire was at its strongest. So I guess when I was most dewy-pure, and felt the most invincible, I must have looked around…"—To Guren, Chapter 5
 * "Once, I was nothing.
 * "You’re damn stupid, you know that? You shouldn’t trust a demon so easily."—To Guren, Chapter 5
 * "Don’t get all sappy on me, with that stupid look on your face. It’s embarrassing, you know… having somebody want you as strongly as that…."—To Guren, Chapter 5

Book 6

 * "Act as nice as you like, Guren, but the real you is still waiting inside… There was a demon living in your heart long before I ever got here. You always wanted to bow to no one, always wanted to have it all. Remember when you were a child, and you thought that all of your dreams would come true? The truth is, you still feel that way now… The kind of dreams that normal people would have given up on long ago, you hang onto like a child. You want these things so badly you can’t help it, not even if you have to hurt someone else to get them. I think that must be what Mahiru likes about you…. It’s what I like about you, too, Guren. Poor baby, someone killed your daddy. And now you’re trying so hard not to seem angry. Not to cry. Look at you, laughing, playing games with your friends. But all this time… all this time you’ve been thinking of ways to turn the whole world on its head."—To Guren, Chapter 2
 * "I bet other demons don’t have such demanding masters…"—Grumbling about Guren, Chapter 3