I've missed this pairing so I thought why not write some more. For this it's set about a year or so after CoHF, but I'm ignoring some canon for it (Tessa and Jem are still in New York and Ragnor is alive).
Cassandra Clare owns them!
Alec was sleeping rather peacefully, curled in his boyfriends arms. Their evening had been an eventful one, and both had been glad to get to sleep. Magnus had hosted a dinner party and all their friends had attended. It had been a fun night but a late one.
So both of them were thoroughly confused when they woke up at 6AM to the sound of a crying baby. Light was just starting to come in through the curtains, and the canary yellow covers were strewn across them.
"What the-?" Alec shot up, effectively flinging Magnus to the other side of the bed. His head swam and he nearly fell back down.
"Alec, it's too early to be awake!" Magnus groaned, burying his head back into his pillow.
"Can you hear that?" Alec's Shadowhunter senses were going into overdrive. They were both quiet for a second and the crying continued.
"Is that...a baby?" Magnus looked at Alec, who shrugged. They both got up and made their way out of the bedroom. The crying got louder as they made their way through the apartment.
The crying seemed to be coming from the other side of the couch, so Magnus leaned over it and saw that there was indeed, a baby crying on the floor in a blanket. He jumped over the couch and scooped the baby up into his arms. Alec joined him on the other side of the couch.
The baby couldn't be more than a few days old, a tiny thing with startling blue-green eyes and little tufts of black hair. She seemed to have some of Alec's features and some of Magnus's features, only slightly paler skin than his. She was bundled up in a pink and purple striped onesie and quietened down when Magnus lifted her up.
"Why is there a baby in our apartment?" Alec asked over Magnus's shoulder.
"Don't know...Do you think that she looks a bit like us?" Magnus yawned, feeling awfully tired. More so than after your average late night and early morning. He yawned again, and sat down on the couch. "Alec, take her for a second will you?"
Alec did as he was told, sitting down next to Magnus and taking the tiny newborn, concern clear on his face. "Are you ok?"
Now Alec got a closer look at the tiny baby, she did look like both of them. She wriggled round in his arms and curled into his t-shirt. Alec knew how to hold a baby, he remembered how he and Izzy used to help his mother, Maryse, with Max when he was younger. He had never imagined, however, that he would be holding his own baby.
"Tired." Magnus leaned on the arm of the couch. "She really does look like us doesn't she?"
"Yeah, she does." Alec nodded. Then something clicked into place. It was impossible, but obviously it had happened since they had the living breathing proof currently drooling into his t-shirt. "Magnus...Do you think she's ours? Like, you subconsciously magicked up a baby? I mean weren't we talking about this last night? And you're exhausted now."
Magnus opened his eyes and looked between Alec and the baby for a long time. Then he groaned and slumped down against Alec's shoulder. Alec took that as a yes.
"So," He took a deep, steadying breath. "We have a baby." A part of him melted and he smiled down at the baby in his arms who was making the most adorable tiny-baby-noises ever.
"What are we gonna name her?" Magnus asked.
"We're keeping her?" Alec croaked out. How the hell could they take care of a baby?!
"Well what else are we going to do with her?" Magnus's eyes were half closed, but he was smiling. "I'm gonna fall asleep." He yawned again.
"We can't take care of a baby!" Alec's eyes were wide, his previous smile had disappeared and had been replaced by a look of mild horror. Magnus could easily hear the panic in Alec's voice as he spoke.
"We could make it work." Magnus kissed Alec's shoulder.
"But we're not ready!" When Alec had said that he had wanted a kid last night he hadn't meant an overnight arrival. The apartment wasn't ready for a baby let alone them!
"Well we'll call in reinforcements and go shopping." Magnus sighed, too tired to magic up anything. "Alec we can make this work."
"I guess we could, but...but what if I'm not a good dad?" The last part was mostly a whisper, but Magnus heard the doubt there.
"Alexander, darling, you'll be a fantastic father." Magnus said with so much conviction that Alec was a little shocked.
"But the apartment isn't ready for a baby!" Alec's voice still had the slight shrill of panic to it.
"We'll go shopping. We'll figure it out. It'll be alright." Magnus shrugged. The baby had wriggled round in Alec's arms to look up at Magnus. "Now what are we going to call her?"
Ok, I have some more of this written if anybody is interested. I have a few ideas of what to call the baby, but input would be appreciated. Hope you enjoyed :)