This is a Fire Emblem Fates fan fiction. Story is based ten years ago but I don't actually know their ages so they might not be accurate.
Nine-year-old Corrin smiled to his seven-year-old brother.
"What do you want to play until Big Brother and Big Sister get here?" Corrin smiled. Leo was currently reading a book more complicated than his age would usually read. In fact, he read the same level as Corrin. They even looked the same age since Corrin's small frame and Leo's slighter broader shouldered than normal frame.
"There'll be here soon. I'd rather finish this book."
"Ah, c'mon! Your big brother says it's play time!"
"No. Later."
Corrin pouted.
"Ppppleeease?"
"Fine."
"Yay! Let's-" Corrin stopped abruptly, as if distracted. Leo looked up from his book.
"Corrin?" He muttered, but the boy was nowhere to be found. Setting down his book, Leo stood up and glanced around the room.
"Brother? Are you here?"
Leo ventured further into the room.
"I'm right here!" Corrin called from the other side of the room and Leo sighed in relief, as he was beginning to get concerned. Leo walked over to his brother who was sifting through a chest of play clothes.
"We can play make-believe if you want, but not with these ridiculous costumes." Leo stated.
"They are not ridiculous!" Corrin defended. "Oh, fine. But why not just a crown? You always like to pretend to be the king and I can be your retainer!"
"Alright, Corrin."
Corrin grinned and handed Leo a black metal crown. He snatched a cloth cloak that was made to look like armor and put it on. By the time Corrin was done, the chest was disheveled with many articles of clothing spilling over the sides. Leo was just about to tell him to clean it up before they begin when he suddenly felt extremely uneasy.
"Corrin, we need to go."
Corrin looked up at him, confused.
"Why?"
"Because I just remembered that Big Brother told us to meet him there instead."
It was a flat out lie but Leo had no desire to alarm his older sibling. Leo had thought he succeeded until he could see the slight unease in Corrin's expression. Pulling off his cloth armor, Corrin set it back in the chest.
"Then why are you so scared, Brother?"
"I am not scared. Let's just get going."
But before they could even start to leave, the cause of Leo's unease was upon them. Someone was sneaking behind Corrin in the shadows.
"Broth-"
Leo tried to warn him but fell to the ground, unconscious. Corrin's huge eyes widened in shock and in fear, both for himself and for his younger brother. He abruptly became aware of two men in the room, one near him and the one who attacked Leo. The two both wore clothes that Corrin had seen similar in books he'd read about ninja.
"Wh-what did you did do t-to my brother?!" Corrin yelped.
"Don't worry, he's fine. Just sleeping." The one near Leo, a young woman, assured. "We're not here to hurt you, we've come to take you to your true home."
"This is my home! Leave me alone!" Corrin wailed, beginning to tear up.
"We apologize, Milord, but we cannot do such a thing." The one near Corrin replied. He could tell that Corrin was about to either start screaming or wailing, loudly. Too loud for their operation, so he covered his mouth and began dragging the squirming child into a secret passage hidden nearby.
...
Leo awoke a few minutes later. As soon as he regained consciousness, he shot upright and furiously scanned the room for his brother.
"Corrin, Brother, are you here!?" Leo called, his voice beginning to break when he realized that he wasn't here. He stood up just as Xander, Camilla, and four-year-old Elise entered the room, Elise holding Camilla's hand.
Xander knew immediately something was wrong from Corrin absence and how Leo looked ready to start crying and wailing. Corrin had only been brought out of his usual solitude because King Garon wanted to assess his progress since he had not seen him from when he kidnapped him. Corrin had already met with him and the King desired to hear Xander's output. Camilla also had her own business. It was a secretive and strictly controlled exchange. But still, Xander had decided to return swiftly after overhearing, (from a reliable source), there was a secret passage hidden around here, fearing the worst. Apparently, he was too slow.
Also, Leo rarely ever acted his age. He was mature, intelligent and cried very seldom. Thirteen-year-old Camilla, being the one who took joy in always comforting her younger siblings, instantly saw the danger as well. She decided to be the one who said what no one wanted to ask or know the answer to. Well, she was about to anyway.
"Where did Big Brother go?" Elise asked innocently.
No longer able to contain his composure, Leo burst into tears.
"W-we- were just pl-playing here and some people came... and... and... They took Corrin away!"
Elise, seeing Leo crying and realizing her older brother is in trouble, starting sobbing and wailing too. Camilla pulled her two sobbing siblings into an embrace.
"There, there. Don't worry; your Big Brother will be back soon." Camilla reassured, as she and Xander nodded exchanged a nod which they both understood.
Xander instantly left the three and brushed around to find the passage. He was old enough to remember when Azura was kidnapped. How awful the feeling of uselessness and the thought that you might never see them again. He wouldn't allow it to happen twice, he wouldn't, it wasn't an option. Though, he couldn't think any less of Hoshido or his kidnappers since they were trying to do the same thing as he was. But that didn't mean he would let them take his beloved brother away. As the eldest of his family and as crown prince of Nohr, he would not allow this attempt to succeed.
Knowing the relative location of the passage, it didn't take Xander long to find it. The passageway was not cramped at all, having the capacity to fit two muscular people side by side. Xander hurried through without a second thought. He wondered if they would underestimate him. After all, he was only fourteen but had the appearance of a fifteen, maybe sixteen-year-old. He put the thought aside, focusing all his efforts on continuing through the passage as swift and quick as possible.
...
Sniffling, it seemed Corrin used up all of his tears, all of his voice and all of his energy. No one could hear them in the passage, so the two thought it a bit cruel not to allow him to release everything, even if it made them feel awful about this. They never expected this to be any moral issue, little to no deaths, and a happy reunion. It seemed they hadn't anticipated or thought about how much he would be attached to his family in Nohr. So, instead they focused on the end goal: returning their Queen's child.
However, Xander was not planning to allow them to fulfill this.
"Stop! As crown prince of Nohr, I challenge you!" Xander announced. "And on my honor, I swear I will not leave here without my brother."
Xander would have added something to the lines of, "or die trying" but he knew that Corrin must be hanging onto his every word and knew that would alarm him too much. He, out of nowhere, was refilled of energy and began reaching out towards Xander, extremely relieved by his presence.
"Big Brother!"
The two "kidnappers" were honestly not positive they could defeat Xander. True, they were a high level of strength but they also knew the strength of their Lord Ryoma, whom they could never hope to defeat. Could Xander be the same strength as him? Even if they couldn't, they had a duty to fulfill to Queen Mikoto: they must try their hardest.
"We accept your challenge, crown prince of Nohr."
Xander nodded to them and turned his attention to Corrin.
"Do not disturb our battle, do you understand?"
Corrin eyes were huge with concern and rapt attention but he nodded slowly.
"But you're going to win right?" He asked timidly.
"Of course, losing is simply not an option."
Corrin smiled, confident in his brother's sheer power.
The battle was not an easy battle that much was obvious. Corrin was tempted several times to intervene but followed what Xander had told him to do. Xander eventually reigned victorious. He allowed them to flee after defeated, mind, that they weren't cowardly fleeing but simply fleeing when they knew that this was the only way to make it through. Tactical.
"Big Brother, you're amazing!" Corrin grinned and hugged him. "Thank you so much for saving me! I don't know what would have happened if you hadn't come..."
"There is no need for thanks. As eldest, I must preserve the safety of you and all of your siblings." Xander replied. "Still, I'm grateful that I wasn't too late."
Like a light bulb went off, Corrin remembered something and released Xander.
"Is Leo okay?"
"Hmm? Did something happen with Leo? If you mean his mental state, Camilla is with him right now."
Corrin shook his head.
"When they kidnapped me, they made him pass out somehow. Isn't that bad...?"
"I wonder... Perhaps we should have a doctor look at him, just in case." Xander said. "Though, he was in perfect health when I last saw him and you know how much he would resent that."
"Either way, we should return as soon as possible. The three of them were all quite concerned for your safety. Even Leo was sobbing."
Corrin was upset that he had made them worry so much, but he was also happy that he meant that much to Leo to make him cry.
"Okay, let's go home."
...
As soon as Corrin and Xander returned, Corrin was enveloped in a hug from his three siblings. Leo and Elise, whom Camilla had finally managed to calm down, had started crying all over again. Leo's was much less severe though.
"You poor dear! They didn't hurt you did they?" Camilla worried.
"I'm okay, Big Sister, thanks to Big Brother Xander."
Corrin opened his arm to invite his Xander into the group hug. Camilla followed his gesture.
"It's not a true group hug without you, darling. After all, this wouldn't even be happening if you hadn't intervened."
Xander took a few moments to contemplate whether it be would dignified for the crown prince to join in a group hug. Well, his family had just been through too much and it was his fault for not making it in time. He supposed because of his young age and since he owed it to them, such a gesture was acceptable. But only for a few seconds.
"Thank you, Big Brother! You saved Big Brother!" Elise smiled.
"That's because he's so amazing!" Corrin replied.
"Big Brother is amazin!"
Camilla and Xander only smiled at the two. Soon after, Leo regained his composure and broke away, cueing Xander to do the same. Camilla did so a bit while later and patted Corrin on the head while Elise still was clinging to Corrin and will probably continue to cling on him for several hours.
Leo, however, was embarrassed by how he acted and was beginning to turn a bit red.
"Don't worry, we're not going to tell anyone."
Camilla nodded in agreement.
"What you did was not shameful. It was completely reasonable given the circumstances." Xander added.
Leo looked away from them.
"C'mon, let's play now before we go!"
Xander agreed but only for a few minutes far away from here. He also resolved to only be concerned about Leo's conditions if they seemed unusual which nothing did. But, nothing happened, Leo was fine and Corrin returned back to the Northern Fortress without difficulty.
Fin