The Son of the Dog Star

The Room of Requirement had shifted again, this time into the familiar layout of a practical classroom—thick cushions arranged in rows, lanterns floating gently above, and a blackboard at the front with Defense Club Meeting written in precise, looping handwriting. It all looked oddly official, as though it had always existed.

Most of the group had already gathered. They stood loosely around Harry, buzzing with low excitement. He looked a little uneasy in the spotlight but didn't protest.

The vote hadn't been formal, but it didn't need to be. Everyone looked to Harry, and everyone silently agreed. Even the ones who hadn't spoken much—like Padma or Zacharias—seemed to recognize it was inevitable.

"He's the one they fear," Hermione said, stepping forward. "He's the one with experience. I think we all know Harry should lead this."

A wave of murmurs swept through the room, mostly in agreement.

Cassian said nothing; he knew this would happen. He stood apart from the group, arms folded tightly, expression unreadable.

"Brilliant," Fred muttered. "So when's the naming ceremony? Do we get badges?"

Someone—Ginny, it sounded like—suggested, "What about Dumbledore's Army? It's what the Ministry's afraid of. Might as well give them a reason."

That drew a mix of chuckles and uneasy glances. A few students clapped at the idea.

Cassian's voice cut in, sharp and flat. "You really think this is funny?"

Everyone turned.

"You're organizing a rebellion like it's a game," he said, his gaze sweeping the room. "This is the Ministry; they're not going to laugh when they catch you. You'll be lucky if they just expel you."

Ron bristled. "No one asked you to be here."

Cassian raised an eyebrow. "Trust me, I noticed."

Before anyone else could speak, Ginny stepped forward beside her brother. "Then why are you here? If you're just going to stand in the back and sneer at everything we do, maybe you should walk out."

Cassian's jaw tightened. "Maybe I should."

He turned, already halfway to the door with Blaise following.

Blaise smirked and called over his shoulder, "Good luck turning this playground into an army, guys."

Hermione stood firm, blocking Cassian's path. "Cassian, please. We asked you here because you're skilled and we need every skilled wand to teach everyone."

Cassian glanced at her, then at Blaise, who had fallen into step beside him, his expression dark with impatience.

Blaise muttered, "I'm sick of everyone here acting like they're better than us—like we don't belong."

Cassian's eyes narrowed. "Look, I won't be part of this if you're all going to treat it like a game. This isn't a joke."

He took a slow breath, voice low and steady. "Umbridge is dangerous. This isn't just some schoolyard rebellion. She's the Ministry's iron fist, and if we underestimate her, we'll all pay the price."

Hermione's gaze didn't waver. "We know that. And that's why we need you. You're one of the best in our year."

Cassian hesitated, then his eyes drifted toward Luna, who was watching quietly from the side, her usual calm presence steady amid the tension.

He took a slow breath, voice low and steady. "Fine. But I'm not here to babysit. I'm here because this has to be serious. If it becomes anything less, I'm out."

—

The Room of Requirement buzzed with soft chatter as students gathered in loose clusters, wands in hand, waiting for the lesson to begin. Harry glanced around, then made his way toward Cassian, who stood slightly apart, arms folded and watching the group like a hawk.

"We should start with Expelliarmus," Harry said under his breath. "It's basic, but it's useful. Easiest way to disarm—"

Cassian didn't look at him. "And useless if they've already cursed you. Start with Protego."

Harry frowned. "Some of them can barely hold a wand properly. They'll need time."

"They don't have time," Cassian muttered. "These aren't mock duels, Potter. We're not playing classroom games. You know who we're up against."

Harry's jaw tensed. He looked back at the others—at Neville, shaking out his wand hand; at Lavender, laughing nervously with Seamus. "They're not soldiers."

"They need to be," Cassian said coldly. "Or they'll end up like Cedric."

That struck a nerve. Harry's lips pressed into a thin line. He didn't respond.

Cassian turned on his heel, voice cutting through the room. "Groups of four. Shield Charms. Sort yourselves—now."

After looking to Harry for approval, students moved quickly. Blaise claimed a corner group with Zacharias, Padma, and Dean. Harry began calmly arranging another cluster of students on the far side, his demeanor far more relaxed.

"Focus your magic here," Harry said, demonstrating the circular wand motion. "Let your intent steady the shield—it's as much about your mind as your wand."

Across the room, Cassian's group was starkly different. His eyes scanned the students sharply, his tone brisk and unforgiving.

"Form matters," Cassian barked. "If your shield falters, so do you."

Ginny struggled with her shield, her wand movements shaky and her charm flickering.

Cassian stepped closer, his voice low and intense. "Your wrist is too loose. Control your magic, Ginny. Again."

Ginny's jaw tightened, frustration flashing in her eyes. "I'm doing my best."

Cassian's gaze didn't waver. "Your best isn't enough. You're going to need more than 'best' when Death Eaters come knocking."

Ginny bristled. "Maybe you forget this is supposed to be a learning space. You don't have to be so mean."

Cassian's expression hardened. "Death Eaters won't care about kindness. This is about survival. If you want to make it through, you learn to be ruthless."

Harry watched from across the room, arms crossed, his face tight and unhappy as he watched the exchange.

Ginny glanced toward Harry, then back to Cassian, determination flickering in her eyes.

"I'm not quitting. I want to learn!"

Cassian's eyes flicked sharply to hers before he turned away. "Good. Then keep up. No excuses."

The lesson pressed on, the students caught between Harry's steady encouragement and Cassian's hard-edged discipline—both preparing them for the dangerous days ahead.

—

In the weeks that followed, the Room of Requirement became a sanctuary for progress. Under the combined guidance of Harry and Cassian—two very different brands of leadership—the D.A. honed their skills with growing confidence.

Harry focused on encouragement, patience, and steady technique. Cassian, meanwhile, drilled them with military precision, barking corrections and demanding improvement with every session. His group, though often sore and occasionally bruised, progressed quickly—sometimes faster than they realized.

Hermione's cleverest idea came not during practice, but after it: a set of enchanted coins, each one bearing a shifting serial number that revealed the date and time of the next meeting. Cassian had inspected one skeptically before pocketing it with a shrug.

"Useful," was all he said. "Still don't trust anything that doesn't explode when tampered with."

Now, with November deepening into chill and frost, anticipation buzzed through the castle—not for the next D.A. meeting, but for the Gryffindor vs. Slytherin Quidditch match that loomed Saturday morning.

Cassian had no interest in Quidditch, but Blaise dragged him to the pitch regardless.

"Come on," Blaise said. "It's not about the sport. It's about watching people fall off brooms in dramatic fashion."

Cassian snorted. "Well, when you put it like that."

They found seats high in the stands, Cassian's dark robes pulled tightly around him as wind whipped past. The Gryffindor section was already roaring with excitement, red and gold flags fluttering wildly.

Then came Luna.

She wandered up to their row with a dreamy smile and a massive lion's head on her own. It roared—loudly—at regular intervals, startling the people sitting around her.

Cassian blinked. "Is that… screaming?"

"It roars," Luna said serenely, sitting beside him as the lion let out another echoing snarl. "I charmed it myself."

Blaise leaned forward, mock-horrified. "Et tu, Lovegood? Betraying your loyal friends in such a manner?"

Cassian shook his head solemnly. "First Gryffindor colors, next you'll be asking the Sorting Hat for a refund."

Luna shrugged lightly. "I just think their team isn't as mean as yours."

Cassian snorted. "Mean doesn't matter. If you're going to play, you play to win."

—

The whistle blew. The match began.

Gryffindor and Slytherin soared into the sky like opposing flocks of hawks, red and green blurs weaving through sharp winds and low clouds. The stands roared as Madam Hooch's whistle echoed across the pitch.

Cassian leaned forward slightly, watching the broom formations with a critical eye. "Slytherin's box formation is tighter," he muttered. "They're going to try and blitz Ron early."

Blaise folded his arms behind his head, lounging in contrast. "Well, that or hope he soils himself midair. He's been nervous all week."

Luna's lion hat let out a fierce roar beside them, startling a few third-years sitting below. She didn't react, sipping something suspiciously fizzing from a corked bottle. "Gryffindor will lose," she said dreamily. "But only because the wind spirits are cross today."

Cassian gave her a sideways glance. "Right. Wind spirits. Clearly the deciding factor."

Luna tilted her head at him. "You've never played Quidditch, have you?"

"No," he replied flatly.

"I can tell."

On the pitch, the match quickly descended into chaos. The Slytherin Beaters began targeting Ron almost immediately, sending Bludgers whistling dangerously close to his broom. The Gryffindor crowd groaned collectively as Ron flailed, barely dodging a hit.

Cassian winced. "He's not reading the field. He's reacting instead of anticipating."

Blaise smirked. "So… not everyone's cut out to be a Keeper. Pity."

"Shut it, Zabini," snapped a nearby Gryffindor girl, glaring at them.

Cassian ignored her, eyes still tracking the game. Fred and George Weasley were playing aggressively, managing to keep Slytherin's Beaters partially in check, but it was clear their team was off-balance. Katie Bell took a nasty hit to the shoulder and dropped the Quaffle. Slytherin scored again.

"Ugh," Luna sighed. "They're not harmonizing at all. They're out of rhythm."

"You mean they're playing like they've never practiced with a blindfolded troll," Cassian muttered.

Draco Malfoy was neck-and-neck with Harry, both Seekers streaking through the sky, ducking Bludgers and narrowly avoiding collisions. Malfoy wore a smug, concentrated expression—but his eyes frequently flicked sideways to sneer at Potter rather than focus on the Snitch.

"He's not really trying to catch it," Cassian noted. "He's just trying to mess with Harry's head."

"He's good at that," Blaise said. "His one actual talent."

Below, Ron had just missed another save, and the Slytherins erupted into cheers. Cassian winced as Ron hung his head.

"Poor kid's going to combust," Blaise said, watching the crowd's reactions with disdain.

"Just nerves," Cassian replied, tone almost neutral. "But this isn't a game you play nervously."

Up above, Harry suddenly dived—and so did Malfoy. A glint of gold streaked between them. Luna clapped her hands, lion hat roaring.

"They've spotted it!"

The two Seekers spiraled downward, dodging a Bludger Fred had just smashed straight at Draco—it barely missed him. The crowd surged to its feet, screaming.

Then—with a triumphant yell—Harry grabbed the Snitch.

And then immediately was hit by a bludger.

Cassian stood abruptly. "That was late. Filthy hit."

"Crabbe, I think," Blaise muttered, squinting down at the pitch.

Madam Hooch's whistle shrieked again, this time full of fury, as she zoomed toward the players.

On the ground, Gryffindor Chasers and Beaters were already converging on Harry. Cassian tracked them with narrowed eyes—Angelina looked furious, and the twins weren't far behind her.

"Uh-oh," Blaise said, pointing.

Malfoy had landed and was strutting toward them, that smug curl on his lips even visible from a distance. The moment he opened his mouth, Fred and George visibly tensed.

"They're too far," Cassian muttered, leaning forward. "Can't hear a damn thing."

But something had clearly been said.

Harry, who had been holding George back, suddenly let go. Before anyone could stop him, he lunged—and from their spot in the stands, Cassian and the others saw Malfoy stagger backward, clutching his face.

Fred broke free next, and chaos erupted on the pitch.

Madam Hooch dove in, wand raised and shouting—her voice just barely carried over the crowd. Cassian couldn't make out the words, but he could guess.

Cassian's eyes narrowed as he watched Malfoy writhe on the ground, clutching his face, and Harry being pulled off him. The crowd erupted, but Cassian's mind raced beyond the noise.

He glanced toward the judges' box, spotting Umbridge's pale, unreadable expression—just the slightest hint of a satisfied smirk tugging at her lips.

He leaned close to Blaise, voice low and grim. "This wasn't spontaneous. Umbridge put Malfoy up to it. She wanted Potter to lose his temper, to give her the perfect excuse."

Blaise raised an eyebrow. "So she's baiting him, waiting for him to hit back."

"Exactly," Cassian said, his tone cold. "She can't openly punish Potter for everything—yet—but if Potter throws the first punch, it's on him. She gets to make him look like the troublemaker, justify whatever punishment she wants."

Behind them, Luna's lion hat let out another loud roar.

Cassian shook his head and turned away, wondering how badly Umbridge would punish Potter for this.