Corban Yaxley—a Death Eater. After the First Wizarding War ended, along with Lucius Malfoy and others, he claimed to have been controlled by Voldemort's Imperius Curse and forced to commit countless wrongs, then was released without charges. But anyone who knew him understood the truth—this man was a Death Eater through and through.
Now that Voldemort had returned, under Barty Crouch Jr's threats and inducements when he came knocking, Yaxley ultimately returned to Voldemort's side. After punishing him for his past betrayal, Voldemort forgave him and allowed him back into the fold.
Of course, Voldemort also valued Yaxley's background as a Ministry official. He needed a Death Eater who obeyed him to remain in the Ministry. In fact, if Sean hadn't shown up today and the person controlling Karkaroff couldn't successfully retreat with Harry, Yaxley—serving as backup and contingency plan—would never have appeared. Now that he'd revealed himself, he had to permanently silence Sean.
Otherwise, at least until Voldemort truly returned, Yaxley might be unable to return to the Ministry.
Must kill him.
Yaxley gripped his wand tightly. Without waiting for orders from whoever controlled Karkaroff, he directly cast a Killing Curse at Sean.
"Avada Kedavra!"
The instant he saw that sickly green light, Sean dropped low and burst forward at inhuman speed, the curse screaming past where his head had been a heartbeat before. His wand came up as he closed the distance.
"Expelliarmus!"
Sean's Disarming Charm, honed through day-and-night practice with Moody's assistance, had reached Level 4. At this level, his casting speed had reached an astonishing degree, even beginning to achieve preliminary effects of nonverbal and wandless casting.
The red light crossed the space between them in an instant.
Yaxley's eyes widened in shock. How could it be so fast! Was he really only a fourth-year?
As a Death Eater who'd participated in the First Wizarding War, Yaxley immediately waved his wand, conjuring a Shield Charm.
But Sean was already pointing at the ground beneath Yaxley's feet. The earth churned like a living thing, surging upward in a crushing wave of soil and stone.
Yaxley's eyes bulged. Abandoning his shield, he thrust his wand skyward. White light erupted from the tip, flash-freezing the descending avalanche mid-cascade.
Though Yaxley's reactions were quick, for Sean, this instant was already enough.
"Stupefy!"
Red light shot forth, crossing the distance in a blink.
A figure materialised before Yaxley, wand moving in a fluid arc. A blue-white halo rippled outward, deflecting the Stunning Spell harmlessly aside.
"Can't even handle a fourth-year Hogwarts student. Yaxley, you're becoming more and more useless."
Hearing Karkaroff's words, Yaxley glanced at Harry Potter, whom Karkaroff had dropped to the ground. His expression shifted. "What's going on? Why did you put Harry Potter down?"
Karkaroff studied Sean carefully. "We can't defeat him. Worthy of someone even the Master values—the intensity of those spells just now definitely isn't something a fourth-year student could achieve. It seems the Master's guess was correct. This Sean Bulstrode really is..."
He didn't finish, but Yaxley already understood.
Involuntarily, Yaxley stepped back, regarding Sean with renewed wariness and fear.
"The Master's orders—what do we do?"
Karkaroff glanced at Yaxley and stuffed something into his hand. "Go back. With this item, the Master's task is complete."
"This is..." Yaxley resisted looking at what was in his hand and turned to Karkaroff. "Aren't you coming back?"
Hearing Yaxley's words, Karkaroff sneered. "This body isn't mine anyway. Whether I return or not doesn't matter. Besides, Karkaroff himself is a traitor. Master gave him a chance, yet he still hesitated and didn't want to return to the Master's service. Such a person has no need to live.
Go. The Order of the Phoenix and Dumbledore are almost here. Once they arrive, you really won't be able to leave. Of course, don't think you're so important. If Master didn't need manpower right now, you wouldn't be worthy of me holding them off for you."
"I understand."
Yaxley stepped back and sprinted toward the Hogwarts boundary. Once beyond Hogwarts' limits, he could Apparate away.
Seeing Yaxley trying to flee, black smoke surged from Sean's body as he launched into pursuit.
A flash of green light erupted from behind, forcing him to bank sharply. The curse tore through the space where he'd been an instant before.
"I won't let you leave so easily, Sean Bulstrode."
"You're Barty Crouch Jr, aren't you?"
"You know me?" Karkaroff—or rather Barty Crouch Jr—looked up at Sean. "Master once told me not to directly conflict with you, but I really want to see just how much of the Master's ability you possess."
"Want to see my abilities? That's fine, but won't you come personally?"
"You'll see me. You definitely will."
With these words, Barty Crouch Jr, controlling Karkaroff's body, suddenly raised his wand. Green light erupted from its tip like a cascade.
Barty Crouch Jr was formidable. When he graduated from Hogwarts, he already possessed power many wizards only achieved in middle age. Because of this, after becoming a Death Eater, he received great attention from Voldemort. After getting to know each other deeply, their similar family situations created a relationship different from other Death Eaters—very nearly a father-son bond.
So Barty Crouch Jr also received secret instruction from Voldemort. His magical prowess far exceeded most Death Eaters.
Though Barty Crouch Jr was currently using Karkaroff's body, his formidable magical strength was already evident—like a smaller version of Voldemort himself.
Glancing at where Yaxley had disappeared, Sean simply gave up pursuing him and turned to seriously duel with Barty Crouch Jr.