Disclaimer: All recognizable characters and settings belong to J.K. Rowling.

I've come across a few Harry is really Draco's younger brother stories and I wanted to try my hand at one...

Warning for scenes of corporal punishment, nothing too excessive but if it will bother or upset you then please skip this fic. There is also family fluff and emotions and brotherly love =)

AU and no horcruxes

1985 – Malfoy Manor

Five year old Draco Malfoy looked at the small baby in his mother's arms. His little brother Cassius had just been brought home from the hospital. "Mother, can I hold him?" he asked eagerly.

"Yes but you have to be very careful," Narcissa said, smiling at her oldest son. He had been so excited ever since he had been told he was going to be a big brother. "Sit on the sofa and then I'll put him in your arms."

Draco obeyed, holding out his arms.

"Gently," Lucius cautioned as Narcissa placed Cassius into Draco's arms. "Hold him like...yes, just like that. You're a natural." he chuckled.

Draco looked down at the little face staring up at him, silver gray eyes meeting silver blue ones. He didn't know why, but he felt an instant connection to this small little baby. A protective surge rose in Draco as he kissed his brother's forehead. "Hi cub. I'm your big brother Draco, and I'll always take care of you. Always."

"Aww," Narcissa sniffled as she summoned a camera to take a picture.

Lucius wrapped his arms around her. "Sentimental," he teased lightly.

"Oh, you're thinking it too," Narcissa laughed. She couldn't be more happy. A husband she adored and two sons she loved more than anything.

1 month later – Malfoy Manor

"He couldn't just disappear!" Narcissa cried, falling onto the sofa as her legs wouldn't hold her anymore.

"We'll find him," Lucius ran a hand through his disheveled hair.

Cassius had been put down for a nap and when Narcissa had gone to check on him, he was gone. Their manor was warded and the wards had not gone off so how did someone enter their home?

The floo flared and Snape came through. "No sign of him?" he asked grimly. He was godfather to both boys and had come as soon as he had received Lucius's message.

"No, we're waiting for the Aurors." Lucius said.

"I don't understand, it's not like he could have gotten up and walked away!" Narcissa wept into her hands. A small hand touched her knee and she opened her eyes to see Draco watching her, tears streaming down his face. "Hey dragon." she whispered.

"I want Cass back," Draco whispered back.

Narcissa let out a sob and pulled Draco into her arms. "So do I, my dragon."

Two house-elves popped into the room. "Master Lucius, we have searched the whole house and there is no sign of Master Cassius," Millie reported sadly.

"He's just gone, Master Lucius," Twitchy said, "We cannot detect any other magical presence."

Lucius's shoulders slumped. "Look again. Look outside. There has to be some sign of where my son is!"

"Yes, Master Lucius," Millie said obediently, popping away.

"Twitchy, make sure to question all the other house-elves," Lucius added.

"Yes, Master Lucius," Twitchy said, an odd gleam in his eyes. No one noticed however, too lost in their grief to see the smirk on Twitchy's face.

The Next Day – Dumbledore's office

Dumbledore picked up the prophet, glancing at the headlines before he froze, shock entering his eyes. He read the article about Cassius Malfoy, missing from his nursery room with no leads as to who had taken him. He slammed his hand on his desk in frustration. "Twitchy." He said, waiting for the house-elf who was his spy. Through some impressive magic, if he did say so himself, he had made it where the elf wasn't bound to the Malfoys, and therefore didn't have to obey them. Not that they knew that, of course.

Twitchy popped into his office. "Master Dumbledore?"

"You gave me the Malfoy baby?" Dumbledore stared at the elf. When Twitchy nodded, he shook his head. "Why? You were supposed to bring me a baby who needed a home, not one who already had a home!"

"Master Cassius is better off away from the Malfoy's," Twitchy said stubbornly. "The Malfoy's follow You-Know-Who, they are evil! Even their brat is already evil," he lied.

Dumbledore sighed and sat down, drumming his fingers on his desk. "What is done, is done. I've already glamoured Cassius into looking like Harry, given him the aging potion, cast a spell to put the knowledge a five year old should have in his mind and left him with the Dursley's."

"He is better off," Twitchy insisted.

"Perhaps," Dumbledore said, guilt filling him for what he done. But he had no choice. The real Harry Potter was dead, due to his relatives neglect, and the wizarding world needed him. They needed him to be their hero. He suspected Voldemort would return one day and the the wizarding world needed someone to look to, to put their hopes on. Cassius, as Harry, would now be that person. It was the right thing to do, Dumbledore tried to convince himself. It's for the greater good.

1997 - Hogwarts

Voldemort and his followers stormed the castle after the first week of classes began. Harry and his friends, now seventh years, had begun dueling while the younger students were told to run. Hoping the professors would come soon, Harry faced the creature that had plagued him his whole life. Voldemort looked so smug and Harry felt so empty. He was so tired of fighting, so tired of trying to be strong. He just wanted Voldemort gone so that he couldn't hurt anyone he cared about again. He focused on his love for his friends as he stared at Voldemort, knowing the monster would see his mind. Voldemort flinched slightly. Suddenly Harry changed his thoughts, thinking of all he had missed. Having a family of his own, being allowed to just be a kid. His longing for parental love, for a family filled his thoughts as Voldemort cast the killing curse at him. He imagined being kissed goodnight and tucked in, of being held in comfort after a nightmare, of getting help with his homework. Such simple things, yet something he had never had. Voldemort stared at him in horror as he read his thoughts and he cringed, dropping his wand. It was too much emotion for him, too much sentimentally and as Harry put up a shield, knowing it would do nothing against the killing curse, the most curious thing happened.

The curse somehow rebounded against his shield and hit Voldemort, causing him to fall to the ground with shocked eyes. Voldemort was finally defeated. There was a moment of shocked silence before everyone began cheering. The death eaters froze, unable to believe their master was dead. The professors, who had come running into the hall, began disarming and binding them up. Harry just stood there while his friends cheered his name, looking exhausted, lost and broken. He fell to his knees, his legs not strong enough to support him. I've never been strong enough, he thought wearily. Everyone just kept cheering.

"Come on, mate!" Ron said, patting him on the back. "Voldie's dead! It's party time!"

"Harry?" Hermione said worriedly. "Are you hurt? Maybe you should go to the infirmary."

"Nah, he's fine," Ron said dismissively. He turned around to go cheer with his friends.

"Potter?" Snape walked over, his arms crossed. "Come now, time to go parade yourself around as a teen hero," he sneered.

Harry looked up at him, defeat in his eyes. He had nothing left to give. All these years of trying to be strong, of feeling responsible every time Voldemort hurt someone, of trying to live up to everyone's expectations...he just had nothing left.

Snape frowned and knelt down. "Potter?" Did the boy get hit by a spell?

"I'm just so tired," Harry whispered.

Snape nodded slowly, meeting Hermione's worried eyes for a moment. "All right, let's get you to Madam Pomfrey." he said quietly.

From across the hall, Draco watched his godfather help Potter up, briefly wondering if he was okay. He glanced at Voldemort's dead body, feeling nothing but relief. That monster had ruined his family. His parents had turned to the light and become spies, like Snape, after the whole ministry fiasco. Voldemort had found out and killed them at the end of his sixth year. Draco may not have gotten along with Potter, but he owed him for getting rid of that creature once and for all. He just wished his parents were here to see it. He watched without emotion as his Aunt Bella screamed and ranted about her master being gone while Remus Lupin disarmed her and used the binding spell to secure her. With a sigh, he went to help disarm the few remaining death eaters who still stood frozen, unsure what to do without their master.

/

In the infirmary, Poppy ran diagnostics. "I can't believe you-know-who is gone. It's about time," she breathed in relief. She then frowned as she waved her wand over Harry again. He had fallen into a sleep born of pure physical and emotional exhaustion. "Poor boy. Always so tired and thin," she murmured.

"Always?" Snape asked in surprise.

Poppy nodded. "You've never noticed? The muggles he lives with keep him malnourished. Every summer he returns he is thinner. And he is small for his age, which I believe is because the malnourishment started when he was young."

"Did Dumbledore know this?" Snape demanded. He hadn't seen it himself, hadn't seen anything beyond James in the boy.

"Yes," Poppy sighed. "He said it was important for Harry to remain with his relatives and for me not to make an issue about it to the boy."

Snape clenched his fists. He may not like the boy but that didn't mean he had wanted Potter to be abused. Of course, I abused him verbally for years, he thought with a grimace. He had been horrible to the boy, and he owed his freedom from Voldemort to him. "Have you ever done an in depth diagnostic?"

"No," Poppy said with obvious shame. "Albus told me not to."

"Do one now," Snape said. Obviously the boy had been neglected but to what degree? Had the abuse also been physical? He hoped not, neglect was bad enough. And to think he had thought Potter would be spoiled by his relatives...

"I'll do it," Poppy said, not caring anymore what Albus had to say about it. She should have done it Harry's first year. She began her in depth diagnostic and waited as a orb appeared next to the sleeping boy, gathering information. Her eyes widened.

"What?" Snape asked.

"He's..." She glanced at Harry with a frown. "This is not possible."

"What?" Snape asked again, impatiently.

"My diagnostic says he is twelve," Poppy shook her head. "It also shows he is wearing some sort of glamour."

"Excuse me?" Snape moved over to read the orb himself. "He turned seventeen this past summer, this can't be."

Poppy paled as a more in depth diagnostic results came. "Severus," She murmured.

Snape read it in shock. Not only was the boy wearing a complicated glamour but he had been given Antiquiorem potion when he was a baby. An advanced potion that would age someone. It literally forced you to grow up.

"If he is really is twelve years old," Poppy said slowly. "Then he can't be Harry Potter. So who is he?"

Severus raised his wand. "Parentibus." Two names hovered about the teen.

Lucius Abraxas Malfoy

Narcissa Druella Malfoy

Poppy gasped, her eyes going wide.

"Identitatem." Snape continued shakily.

Cassius Aster Malfoy

"It can't be..." Poppy whispered.

"But somehow is it," Severus said, completely in shock. He was Draco's godfather and he had also been named godfather to their second son, Cassius. He had been just as heartbroken as the Malfoys when the baby had disappeared. Draco especially had been devastated. Even at five years old, he had been ecstatic to be a big brother.

"Can you undo the aging?" Poppy asked after a moment.

"Yes," Snape said. "I need to make the antidote first. Don't let anyone near him, especially Albus."

"You don't think the Headmaster had anything to do with this?" Poppy asked, horrified.

"Who else?" Snape snapped. "Can you work on breaking the glamour?"

"Yes."

/

"Draco, I need to talk to you," Snape said as the blonde entered his lab. He had summoned his godson, unsure how to tell him what he had just discovered. It would be an incredible shock for the seventeen year old.

"I wasn't hurt in the fight, if you're worried," Draco said as he watched his godfather work on a potion. Potions was his favorite subject and he was at the top of his class, next to Granger. "Can you believe Voldemort is finally gone? Potter really did it. I wish..." he trailed off. "I wish my parents were here. They would have been so relived he was gone. And it's my last year here, my mother couldn't wait to throw me a graduation party. Now, there's nothing. I don't even care what I do after I graduate. I have nothing now." He had nothing to hold onto, he felt completely empty. He had his Uncle Sev of course, but still...

"That will change." Snape said as he bottled the antidote he had made.

"Oh?" Draco looked at him curiously.

"Your brother has been found."

Draco froze, his eyes darkening. "That's not funny," he hissed.

"I'm not joking."

Draco stared at him. "Where is he? Is he okay? Where has he been all this time?" He demanded. Cassius was alive?

Snape decided to just be straightforward. There was no easy way to break news like this. "He was taken and given a complex aging potion. He was also glamoured to look like someone else. He's been here at Hogwarts, in your year."

Draco stared at him, his face going completely pale.

"Draco, I don't know how but the boy we thought was Harry Potter is Cassius."

"Not possible!"

"I cast a paternity spell and an identity spell on him," Snape said. "When running a full diagnostic, it read that he was only twelve years old, not seventeen. Madam Pomfrey is breaking the glamour charm now."

"It can't be...Potter? But..." Draco shook his head. "How? Why would someone do this? It doesn't make sense!" How could Potter be Cassius?

"I know," Snape said quietly. "And I plan to find out. But the important thing is, Cassius is alive and is here."

"Cass," Draco whispered. The boy he had taunted and bullied over the years was his brother? "I want to see him."

"Let's go."

/

Poppy looked up when Snape and Draco entered the infirmary. She gave Draco a sympathetic smile. "I've just about broken the glamour."

"I have the antidote that will restore him to his correct age," Snape said.

Their eyes widened as they watched who was thought to be Harry Potter change. His hair turned blonde, a shade or two darker than Draco's. His skin more alabaster, his features now including higher cheekbones, giving him a more aristocratic look. While Draco favored Lucius, it looked like Cassius favored Narcissa.

"Merlin," Draco whispered in awe. "It really is him."

"I need to wake him up," Poppy said as she picked up a vial. "Ca – I mean, Harry," she gave Draco an apologetic look. "Harry, wake up. You need to take a potion."

Cassius's eyes opened slowly and he blinked. Gone were the emerald green. Now they were a silvery blue. He focused on Poppy. "Hmm?" he asked sleepily.

Poppy smiled gently at him. "I need you to take this potion. Here you go, swallow it all down." She urged as she tipped the vial to his lips.

Cassius grimaced as he swallowed. "Yucky," he said after he had taken it.

Poppy chuckled. "I know, I'm sorry. You can go back to sleep now."

"Okay," Cassius sighed and instantly fell asleep. A moment later, his body began to change as he became his correct age.

Draco watched in shock as Pot – no, Cassius basically shrunk before their eyes. He frowned. Even for an twelve year old, his brother was small. "He looks eight or so," he said in confusion when it appeared the potion had finished its job.

"I know," Poppy said sadly.

Draco stepped forward and took his brother's hand. "Why?" His brother, his baby brother, was actually here. He had been here the whole time. Oh Cass, he thought, running his hand through his brother's hair. It now made sense, why he had been so angry when the boy he had thought was Harry Potter rejected his offer of friendship. He had felt a connection, an instinct to protect when he had seen him. Being rejected had hurt him so he had tried to hurt the boy-who-lived. Only this boy wasn't the boy-who-lived, he was Cassius. If only I had known, he thought with anguish. His brother had been right in front of him all these years.

Poppy exchanged a look with Snape. "He was neglected by the muggles he's lived with. He's been extremely malnourished while in their care, it affected his growth. The aging potion would have also taken it's toll on him, it made him skip fundamental years."

"So someone took my brother and made him look like Harry Potter, gave him a dangerous potion and put him with abusive muggles?" Draco's voice was dangerous.

"Yes," Poppy said, biting her lip. "I should have discovered this much earlier," she said with regret. "I shouldn't have listened to Albus..."

Draco's head shot up. "The Headmaster? Did he do this?" He asked in shock.

"We do not know for certain," Snape said.

"But you believe he did," Draco said, his eyes narrowing.

"I will find out, I promise," Snape said.

"Perhaps I should go talk to him," Draco said darkly.

"Perhaps you should stay with your brother," Snape countered.

Draco shut his eyes for a moment before nodding. "I want to know everything. I'm seventeen, I can handle it." He wasn't a kid anymore and losing his parents had changed him, made him grow up faster. And now, he had a little brother to care for, to protect.

TBC: Let me know what you think! Reviews are appreciated! =) Next up, Harry/Cassius reacts to the news!