A.N.: Written for the kink meme:

Brotherhood era, Regis can sense magic being used, knows Noct is in danger
Inspired Harry Potter and how the ministry can tell when a wizard uses magic in the mugle world

Regis can sense any time any magic is used, who is using it, and what they are using it for. One night he wakes up feeling Noctis accessing the arsenal. Obviously something is wrong. He tries and fails to get a hold of Noctis by calling and texting him. He goes into a panic trying to find out about and stop whatever is happening.

I would like this entirely from Regis' perspective: sensing the magic, calling Noctis, Ignis, Gladio, maybe even Prompto, ordering crownsguard sent to Noct's apartment, etc. Really zero in on the mounting anxiety and growing worry. It's up to anon if Noctis really was in danger, if it was a mishap due to being new to magic use, or if Noctis was just being a butt and fooling around.

Disclaimer: Don't own Final Fantasy XV

It happened at three o' clock in the morning.

Regis' eyes snapped open. He sat bolt upright, his breathing fast, his hands shaking, and his knee twinging. He snatched his phone up from where it sat idle on his bedside table and dialled Noctis: the first number on his speed dial.

"Hey, it's Noctis. Leave a message."

Regis scowled. "Noctis, are you okay? I know you summoned a weapon. Please get back to me."

He hung up, then sent the same words over to Noctis in a text.

He waited twenty, maybe thirty, seconds before dialling another number.

"Your Majesty? What's wrong?"

"Noctis has accessed the arsenal and he isn't answering his phone."

Clarus paused. "Shit."

Regis swung his legs off the bed and grabbed his cane. He stood, winced, and made for the door as fast as he could.

"Regis, don't over exert yourself."

"Noctis could be in danger!"

Clarus sighed. "Look, I'm heading for your room right now. Meet me by the door."

"You have thirty seconds."

Regis hung up the phone and wrenched his door open, and Clarus was just a few steps away.

"Clarus!" Regis stumbled forward and grabbed onto Clarus' shirt. "Who's on duty to watch Noctis' apartment?"

Clarus placed his hand over Regis'. "I believe it is two of the Kingsglaive."

Regis tightened his grip. "Where is Drautos?"

"Regis, panicking will solve noting."

"Where is Drautos?"

Clarus sighed. "I am not sure." He pulled his phone out.

Drautos picked up a gruelling ten seconds later.

"Sorry to disturb you at this hour, but do you happen to know which Kingsglaive are on duty to guard the prince's apartment this evening?"

A pause.

"Thank you. Good night." He hung up.

"Who is it?"

Clarus pocketed his phone. "Pelna and Crowe." He raised his head to meet Regis' gaze. "They're trustworthy, you know that."

"Then why is Noctis accessing weapons?"

"I don't know, my love. Are you sure he's at his apartment?"

Regis nodded. "Definitely."

Clarus pursed his lips, thinking. "Could he be showing off? He may not be alone. He may be having a sleepover with Prompto."

Regis swallowed. He reached trembling fingers into his pocket for his phone, and dialled Cor.

"Your Majesty? Has something happened?"

"Is your son in the house?"

Cor paused. "I have every reason to believe so, yes. Why do you ask?"

Regis sighed. "Noctis has accessed a weapon from the Armiger. Clarus posited the notion that he might be showing off to Prompto."

Cor sighed. "I'll ring Prompto, and if he isn't with Noctis, I'll make my way over to the prince's apartment."

"Thank you. Keep me updated."

"Of course, Your Majesty."

"What did Cor have to say?" Clarus asked.

Regis relayed the conversation to Clarus.

Clarus gave a nod. "Try the others."

"Others?"

"Ignis and Gladiolus."

Regis raised an eyebrow. "Why?"

"Because you're going to be fidgeting until Cor texts back, and this will give you something to do."

Regis sucked in a breath, then gave a nod and agreed.

"Your Majesty?" Ignis' voice was thick with sleep.

"Are you with Noctis?"

A pause. "I am not. Why? Has something happened?"

Regis sighed. "He has accessed the arsenal."

"He- Oh… Gladio did tell him to practice. Though at this hour? I couldn't tell you, Your Majesty. I apologise."

"Do not concern yourself, Ignis. I already have Cor on the case, and Gladiolus is my next port of call."

"Very well. Good night, Your Majesty."

"Good night."

"Ignis mentioned Gladiolus?" Clarus asked as soon as Regis hung up.

"Ignis tells me he has instructed Noctis to practice accessing the Armiger."

"At three o' clock in the morning?"

"I don't know!"

Clarus put a hand on Regis' shoulder. "I'm sure we'll get to the bottom of this."

Regis nodded as he dialled Gladiolus.

"Your Majesty? Gladiolus was also groggy, and keeping his voice low.

"Are you with Noctis?"

"I am not. May I ask why?"

"He's accessed the Armiger."

"What? Unsupervised?"

"I fear he is in danger."

Gladiolus sighed. The sound of rustling sounded on the other end of the phone. "I'll head over to Noct's apartment."

"Thank you. Cor is also looking into the matter, and may join you. What about Iris?"

"Jared's in the house. She'll be safe with him."

"Okay. Let me know what's going on when you know."

"Will do."

When Regis hung up, Clarus was watching him.

"What did Gladiolus have to say?"

"He has entrusted Iris' care to Jared and gone to Noctis' apartment."

Regis' phone buzzed.

Prompto's in the house. I'm going to Noctis' apartment.

"And, it would seem, Cor is going over as well." Regis met Clarus' eyes. "Do you think I should go? What if the Empire has found a way passed the Wall? What if there are daemons?"

Clarus squeezed Regis' shoulder. "You would know if the Wall had been breached, and Noctis need only turn on a light to repel any daemons."

"What if they knocked him out first?"

"They would still have had to traverse a good portion of Insomnia undetected."

Regis took a deep breath.

"I should go to Noctis' apartment."

Clarus shook his head. "Wait until Gladiolus and Cor give their repots."

"Anything could have happened by the time they get there!"

"But you cannot get there any faster than them."

Regis fixed Clarus with a resolute look, and Clarus' eyes widened.

"No. Your Majesty, you are not strong enough-"

"I need to try."

"You haven't been able to summon weapons for weeks, you cannot warp!"

"He's my son! I would tear the world to pieces to ensure his safety."

"I know. But there is still a chance that there is nothing wrong."

Regis took a couple of breaths, then conceded.

"I'm still going over to Noctis' apartment."

Clarus gave a nod. "Then I will come with you."

Clarus took the wheel of the Regalia. Regis sat in the passenger seat with one hand on his knee and a pained wince on his face.

As Clarus pulled out of the garage, Regis' phone beeped. A text from Cor shone on the screen.

Noctis is safe and sound.

Regis let out a sigh of relief.

"Noctis is fine. Gladiolus and Cor found him safe and sound in his apartment."

"There you go," Clarus said. "Shall I turn around?"

Regis' phone beeped. It was Cor again.

But I think you should come over, Your Majesty.

Regis blinked and read the message again.

"Your Majesty?"

"No. Keep going."

Clarus hummed. "Alright."

Regis tapped out a reply then sat back in his seat with one elbow on the window and his hand by his mouth.

It took them twenty minutes to reach Noctis' building. Regis' fingers were rapping on his knee brace, and neither he nor Clarus had spoken since Cor's second text.

When they got there, Cor and Gladiolus were in the lobby with the two Kingsglaives.

"Hey, dad." Clarus put a hand on Gladiolus' shoulder and gave him a nod.

"What's going on?" Regis asked Cor.

"The prince has… requested your presence, You Majesty."

Regis furrowed his brow. "What do you mean?"

Cor sighed. "I think… it's best if you go and see him, Your Majesty."

"He isn't harmed in any way?"

Cor shook his head. "No."

Regis pursed his lips. "Very well. Thank you for coming over. And you, Gladiolus."

"Of course, Your Majesty." Gladiolus bowed.

"You are dismissed, all three of you. I will go and see my son."

Clarus and Cor bowed then made for the door. Regis turned to the elevator.

Noctis was lying on his sofa with the Engine Blade lying across his chest, looking for all the world like his own sarcophagus in a Royal Tomb.

Regis swallowed the lump in his throat and closed the door behind him. Noctis turned his head to him. His eyes were blank.

"How's your knee?"

Regis blinked. "Noctis?"

"You walk with a cane now. You wear a brace. How's your knee?"

Regis sighed. "It aches."

Noctis nodded once, then turned away.

"Noctis, do you have any idea how worried I was this evening? I thought you were in danger."

"Well, that was kind of the point," Noctis grumbled.

Regis was silent for a moment. "Noctis, you were the one who wanted to leave the Citadel."

Noctis scoffed. "Cause we saw so much of each other before that."

Regis sighed. "Noctis…"

"I made a friend." He looked back at Regis. "His name is Prompto."

Regis shifted. "I know."

Noctis huffed. "You made any new friends?"

"I have not."

Noctis' eyes glistened, and he turned away. He banished the Engine Blade.

"I… I miss you."

"I miss you too, son."

Noctis gulped. "Will you… will you stay? Just for tonight?" He met Regis' eyes.

Regis gave him a small smile. "Of course, Noctis."

Noctis smiled.