Rin woke to find his right arm covered in strange marks.
They weren't injuries. The patterns looked like tattoos, black lines that formed intricate geometric shapes spiraling from his summoning mark up to his elbow. They pulsed faintly with dark energy.
"Malachar!" Rin's voice cracked with panic. "What is this?"
"Corruption marks," the demon lord responded, his tone unusually serious. "A side effect of our bond. I was wondering when they'd appear."
"Side effect? You didn't think to mention this before?"
"Would you have believed me? Would it have changed anything?" Malachar's presence coalesced into a shadowy form at the foot of Rin's bed. "When you bond with a being from the Nexus, especially one as powerful as me, there are... consequences. The energy I channel leaves traces in your body."
Rin stared at his arm. "Is it dangerous?"
"Only if you let it consume you. The marks are a sign that you're adapting to my power, but push too hard and they'll spread. Cover enough of your body, and you'll start transforming into something neither human nor demon." Malachar paused. "I've seen it happen to summoners in my world. They called them the Corrupted. Powerful but mad, eventually losing themselves entirely."
"How do I stop it?"
"You don't. You manage it. Use my power sparingly. Rest between manifestations. And most importantly, maintain your sense of self. The corruption feeds on doubt and fear."
Rin pulled on his uniform, making sure the long sleeves covered the marks completely. He couldn't let anyone see this. The academy already feared him. If they knew his bond was physically changing him…
At breakfast, Kira noticed immediately. "You look terrible. Are you sick?"
"Didn't sleep well," Rin lied. "Still recovering from yesterday."
"Bond exhaustion is real," she said sympathetically. "You manifested Malachar for almost eight minutes straight. That's intense for a new summoner." She pulled out her notebook. "I've been researching ways to increase bond efficiency. There are meditation techniques, mana circulation exercises"
"Kira, can I ask you something?" Rin interrupted. "Have you ever heard of summoning bonds having physical side effects? Like, changing the summoner's body?"
She frowned thoughtfully. "Some bonds create minor changes. Elemental summoners sometimes take on aspects of their element. Fire summoners run warmer, water summoners can hold their breath longer. Why?"
"Just curious."
"If you're worried about your bond with Malachar, you should talk to Professor Corvin. She specializes in unusual contracts." Kira lowered her voice. "Though between you and me, I think the changes are fascinating. You're pioneering entirely new summoning theory."
Before Rin could respond, a commotion erupted at the dining hall entrance.
Elena Brightstar strode in, followed by her usual entourage, but something was different. Her normally pristine appearance was disheveled, her silver hair slightly mussed, and there were dark circles under her eyes.
She scanned the room until her gaze locked on Rin. Then she walked directly toward him.
The dining hall went silent.
"Eldraven," Elena said, stopping at his table. "We need to talk. Privately."
Rin exchanged a glance with Kira, who looked as confused as he felt. "About what?"
"About what happened to Lumiel after our match." Her voice was tight, controlled, but Rin could hear the underlying tension. "My summon has been... unstable since fighting your demon."
Rin stood slowly. "What do you mean, unstable?"
"Not here." Elena turned sharply and walked toward the exit. After a moment's hesitation, Rin followed.
She led him to a small courtyard behind the dining hall, empty at this hour. The moment they were alone, her composure cracked.
"Lumiel won't manifest properly," she said, her hands clenching. "Since yesterday, every time I try to summon him, he appears corrupted. His light is tainted with darkness. His armor has cracks that leak shadow instead of radiance." She met Rin's eyes, and he saw genuine fear there. "Your demon did something to him."
"I..." Rin's mind raced. "Malachar, what did you do?"
"Nothing permanent," the demon lord responded in Rin's head. "But my power is anathema to celestial beings. When I struck that angel, some of my essence transferred. It will fade in a few days."
Rin relayed this to Elena, whose expression hardened. "A few days? The monthly ranking tournament is in three days! If Lumiel can't fight properly, I'll drop rank. Do you understand what that means for me?"
"I'm sorry, but it was a sanctioned match. You challenged me, remember?"
"I challenged you to test your control, not to have my summon corrupted!" Her voice rose, then she forced herself to calm down. "There has to be a way to cleanse the corruption. Some kind of purification ritual."
"The corruption is part of what I am," Malachar interjected. "There's no cleansing it without me actively withdrawing my essence. And that would require direct contact between myself and the angel."
Rin hesitated, knowing what he was about to suggest was risky. "Malachar says he can remove the corruption directly, but he'd need to manifest and make contact with Lumiel."
Elena laughed bitterly. "You want me to let the demon who caused this problem touch my summon again? Are you insane?"
"It's either that or wait for it to fade naturally. Your choice."
She was silent for a long moment, clearly warring with herself. Finally, she spoke through gritted teeth. "Fine. But if your demon makes it worse, I will personally ensure you're expelled from this academy. My father has enough influence for that."
"Understood."
Elena activated her summoning mark. Light burst forth, but Rin could immediately see what she meant. The radiance was dimmer than before, shot through with veins of shadow. When Lumiel fully materialized, his usually pristine armor was indeed cracked, darkness leaking from the fissures like infected wounds.
The angel's voice sounded strained. "Summoner, I am... compromised."
"I know," Elena said softly. "We're going to fix this."
Rin summoned Malachar, who appeared in his full form. The demon lord studied the corrupted angel with something like professional interest.
"Interesting," Malachar said. "The holy essence is fighting my corruption, creating a feedback loop. No wonder the angel is suffering." He approached slowly, hands raised in a gesture that was almost peaceful. "Hold still, celestial. This will be unpleasant."
He placed a hand on Lumiel's chest, where the largest cracks congregated. Dark energy flowed from his palm into the angel, and Lumiel stiffened, a sound of pain escaping his throat.
Elena took a step forward, but Rin held up a hand. "Wait. Let him work."
Malachar's eyes closed in concentration. Through their bond, Rin felt the delicate process: Malachar was calling back his corrupted essence, pulling it out of Lumiel's celestial form like extracting poison from a wound.
It took nearly five minutes. When Malachar finally stepped back, Lumiel's cracks were closing, the darkness receding. The angel's light grew stronger, clearer, until it was once again the radiant being Rin had seen before.
"Done," Malachar said. "The corruption is removed. Your angel is whole again."
Lumiel tested his limbs, spreading his wings. "I am... restored. Thank you, demon." The words sounded grudging but genuine.
Elena dismissed Lumiel and turned to face Rin. Her expression was complex, mixing relief with resentment and something else. Respect, maybe?
"I owe you a debt," she said quietly. "I don't like owing anyone anything, especially you. But you kept your word, and your demon fixed what he broke."
"We're even then," Rin said. "The match was fair. What happened after was an accident."
"Perhaps." She studied him for a moment longer. "You're not what I expected, Eldraven. Most people with that kind of power would have refused to help, would have used it as leverage. You just... did the right thing."
"I'm not trying to be anyone's enemy, Elena."
"No," she agreed. "But you will be anyway. Power makes enemies whether you want them or not." She turned to leave, then paused. "One more thing. There are rumors circulating. Some of the senior students are planning something. I don't know what, but your name keeps coming up. Be careful."
She left before Rin could ask questions.
"Well," Malachar said as he dissolved back into shadow, "that was unexpectedly civil."
"She's not as bad as I thought," Rin admitted.
"Don't mistake pragmatism for friendship. She helped you because it served her interests."
"Maybe. But she also warned me about something."
Back in his room that night, Rin examined his arm. The corruption marks had spread slightly, now reaching past his elbow toward his shoulder.
He thought about what Malachar had said. Manage it. Don't let it consume you.
But how long could he manage it? How many more battles could he fight before the corruption took too much?
And what would happen when it did?