Clary had never had any siblings. Simon was her best friend, and they'd grown up together, so he was kind of like her brother, but it wasn't the same. Now she had a brother, but they'd only known each other for a few weeks and their relationship was more than a little… awkward and confusing.

She had no idea how she was supposed to act around him and it was bad enough that they'd kissed. It was all so confusing and she decided she should probably do some research about how siblings worked.

Simon and his sister had always been around but she'd never had to analyse their behavior and now Simon couldn't see his sister. So, she could look to them as a guideline. So, she was left with Alec and Izzy, but they were confusing.

Clary could never be sure what was happening between those two, it was like they had their own secret language or something. Sometimes they wouldn't even speak but it was like they had a whole conversation and Clary had briefly wondered if there was a telepathic rune that she hadn't been told about.

Clary had watched the silent conversation carefully and still didn't know what it meant.

Jace had been going over a mission and needed Magnus to open a portal. So, someone would have to call him. Izzy had smiled and given Alec a look to which he had seen and frowned at. Izzy merely smiled wider and raised her eyebrows, tilting her head slightly. Alec frowned harder and threw out his hands as if asking what her problem was. So, Izzy crossed her arms and tilted her head the other way, making Alec roll his eyes and give in.

"Fine. I'll call him, Izzy, just stop. And he's not my boyfriend."

Clary had been severely confused about what had happened. Alec had acted as if she'd been talking aloud through her head tilts. For all she knew, she had been, just at a frequency only Alec could hear. As if that wasn't bad enough they seemed to bounce between having fights and loving each other within the span of ten seconds.

"Alec, would you stop! It's not the same and you won't understand because you've always been Mom's favorite!" Izzy had been so upset that she wouldn't look at her brother and Alec had deflated from his rigid stance, sighing as he studied the floor. But after a few moments he'd started smiling and lent on the table next to Izzy.

"Do you remember that time Mom and Dad went to Idris and left without singing us to sleep? And you insisted you couldn't go to bed until she sang?"

Izzy started smiling too, sad eyes softening and she recalled the story.

"Yeah, so you dragged me to your bed and said it was a cheat. I couldn't sleep in my bed but I could sleep in yours and the monsters would look in my room and think I was gone and leave me alone."

They both laughed and looked at each other with quiet smiles. Clary watched the exchange. No "I'm sorry's" no "I forgive you's" just… a memory? And that had been the end of the fight.

Were all siblings this way? How was she and Jace supposed to do that? She barely understood what he was saying when he was speaking actual words.

Or even worse, they'd be in the middle of a fight and get called to do something.

"You don't ever listen to me? Why don't you trust me?"

"I do trust you Izzy it's just- dammit, I have to go. Jace found that other vamp."

"Fine. Be careful, I love you."

"Love you too." And Alec would kiss her forehead and be gone, leaving Izzy as grumpy as she had been before and they would resume their fight when he got home.

The only thing that seemed to be stay constant was the love they both had for each other. It was unconditional and never ending.

Alec could be mad at any of his siblings and still stick up for them at any given moment. Clary had thought Alec would do that in battle, sure, and for his Parabatai because they were linked. But Alec always told others off if they spoke badly about his sister, even if he had been doing the same thing three seconds before.

"Hold your tongue or I'll cut it out of you. You don't get to talk about her."

And just a look from Izzy would stop any chatter about her brother and the warlock he'd made out with.

Clary had been especially surprised when Alec, broody, grumpy, perpetually miserable Alec, would smile or become the biggest softie ever, just because it would make his little sister happy.

Izzy had sprained her ankle during a mission and was unable to put any weight on it. So, Alec, without a second thought, had knelt down and ordered her to get on.

"I'll give you a piggy back ride just don't strangle me with your whip."

Izzy had happily climbed on and wrapped her arms around Alec's neck, as he stood and carried her home. Clary hadn't been able to stop laughing as the shadowhunter ordered people around with his sister clinging to his back.

"Move your ass Raj, and I want that seelie found and brought here, unharmed."

"Um, Alec I-"

"That's an order."

The others nodded and went about their business while Alec tried to look stern and grumpy with Isabelle playing with his hair, still on his back.

And then there were the times Alec threw out every piece of shadowhunter training he had, and allowed himself to be almost killed, because he couldn't bear the thought of hurting his sister.

Clary had watched as Izzy crouched over Alec, digging her nails into his chest as she prepared to bury her hand on his chest. And Alec had just pleaded with her. He hadn't been able to shoot a single arrow at her, regardless of how many ways he could take her down without causing any lasting damage, and he hadn't been able to throw any punches either. Because hurting his sister in any way was unthinkable.

So, he lay there with tears in his eyes and waited to die. Clary didn't want to hurt Izzy either but knew that if the demon inside her got free, it would only destroy more people. Clary stabbed Isabelle and killed the demon, and Alec took care of his sister. Even as his shirt grew damp with blood from the claw marks on his chest, he hugged his sister and told her everything was okay.

Clary had even heard Alec lie to Izzy, saying that he was fine, she hadn't hurt him.

It was then that Clary realized Alec and Isabelle would always love each other more than they loved themselves and that Alec would always choose Izzy over anyone else, even his Parabatai if he needed to.

Having an older brother meant having someone to always love and protect you, someone to be proud of you when you beat the ever-living shit out of some gross mundane. Someone that would always be there when you needed them and could always be trusted to be on your side.

Alec may not have been the nicest person but he was a damn good big brother, and he always would be.