Isaac thought it was a shame.
In a world where interrupting a spell caused magical backlash, that dark wizard would have been in real trouble.
Unfortunately, Harry Potter's world had no such mechanism.
At worst, a failed spell left a wizard gasping for breath.
And they were inside a house, with no wind to take the dark wizard's breath away.
"You damned Mudblood!"
The dark wizard flew into a rage. He tossed the "baseball bat" aside and pulled a new wand from beneath his robes.
"Crucio!"
"Crucio!"
"Crucio!"
Three Cruciatus Curses shot from his wand in quick succession, each carrying more malice than the last.
By the third curse, that malice had peaked.
So had his desire to torture Isaac.
Unfortunately for him, not one of the curses hit.
Each spell skimmed past Isaac by a hair and struck the wall behind him.
After "narrowly and desperately" dodging all three, Isaac flashed the dark wizard a brilliant smile.
"Nice shooting~"
The dark wizard's already frayed grip on reason snapped. His eyes bloodshot, he pointed his wand straight at Isaac.
"Avada—"
"Expelliarmus!"
A red spell streaked from Isaac's wand and struck him instantly.
The green-glowing wand flew from the dark wizard's hand the moment the spell hit, spinning toward Isaac.
The Disarming Charm was the only intermediate spell besides Transfiguration that Isaac had studied before school. It was also a staple of wizarding duels.
In Harry Potter, Harry had practically turned it into a red welding beam capable of clashing with the Killing Curse.
Truly an indispensable spell for home, travel, and visiting friends and family.
Naturally, Isaac had to give such a versatile spell a proper try.
At first, he had thought it was nothing special. Now, though...
Against an enemy who couldn't use Wandless Magic, the Disarming Charm was genuinely useful.
The dark wizard, for instance, could only watch as Isaac cast his next spell.
"Incendio!"
The moment he lost his wand, the dark wizard lost his sense of safety and lunged at Isaac.
Then he heard Isaac call out the Fire-Making Spell.
A child's trick. Strictly speaking, though, the Fire-Making Spell could do plenty of damage.
Set a mountain ablaze, after all, and you could spend the rest of your life behind bars.
The trouble was that it had a counterspell. There were even spells specifically suited to defending against it.
Aguamenti or a Fire-Protection Spell would do the job, and even Protego could hold it off for a while.
If only he could get hold of a wand.
The dark wizard expected the flames to come at him. Instead, Isaac pointed his wand at the floor.
Crimson fire sprang up. Then, like the rings of a gas burner igniting one after another, it spread outward in roaring circles.
The last thing the dark wizard saw was Isaac grinning at him from the center of the flames.
His lips seemed to be forming another incantation.
What was it?
"Protego Ignita!"
The instant Isaac finished the incantation, crimson flames surged toward the dark wizard as he lunged through the air.
The torrent swallowed him whole.
And not just him. His two wands on the floor, the villa's furniture, even the entire villa fell within the flames' reach.
"Ha... haha, hahahaha!" Oblivious to the heat, Isaac stood laughing wildly on the only patch of floor the flames had spared.
"Dumbledore, help me!"
The moment his laughter ended, Isaac called for help.
Standing at the center of his Fire Shield kept the flames from consuming him, but it did nothing to stop the villa's burning debris from falling on him.
Perhaps Grindelwald's original Fire Shield offered genuine protection.
Isaac's version was a youth edition, though. Even its incantation differed from Grindelwald's.
As Grindelwald had said, Isaac hadn't even met the prerequisites for learning the spell.
Getting a youth edition to work at all was impressive enough.
For all its spectacular appearance, it was basically useless against skilled wizards.
They could simply use a counterspell, or even Finite Incantatem.
As soon as Isaac called out, Dumbledore appeared beside him in a flash.
Dumbledore raised his wand, barely moving it.
"Finite."
The raging flames vanished as though erased, revealing the battered villa and the dark wizard lying at death's door.
Isaac's youth-edition Fire Shield could be dispelled with Finite Incantatem, but the dark wizard clearly couldn't use Wandless Magic.
Without a wand, he had no choice but to burn.
The good news: St. Mungo's Hospital for Magical Maladies and Injuries had well-established treatments for wizards burned by "ordinary fire."
He wouldn't even need to be admitted. A little treatment on-site would heal him.
The bad news: being healed didn't mean he would remain free. He had attacked a young wizard right in front of Dumbledore.
He had even used an Unforgivable Curse... Azkaban was about to welcome another Hogwarts graduate.
Having a party without me? Fine, I'll show up myself!
Once the flames were completely gone, Dumbledore waved his wand again at the villa's ruined interior.
It was as if time had reversed. Everything the fire had burned, the spells had damaged, or the dark wizard had smashed was restored.
Within seconds, the entire villa was back to how it had been before the fight, inside and out.
"Reparo," Isaac said, naming the spell Dumbledore had used.
The same spell could produce entirely different results in different hands.
Isaac, for example, couldn't manage such precise repairs on such a large scale.
It came down to practice.
Isaac breathed a sigh of relief when he saw the villa restored. Grindelwald had only lent him the place to stay in, after all.
He couldn't very well return it in ruins.
After cleaning up the aftermath, Dumbledore cast a Binding Charm on the fallen dark wizard and lowered his wand.
His Mending Charm had not repaired the dark wizard's wand.
The man would have no need for one anymore.
Dumbledore stared at Isaac, lost in thought. Isaac knew he wasn't really looking at him.
He was looking through Isaac at someone else.
What am I, a bridge to the past he can use to send letters?
"Isaac, that spell just now..." Dumbledore's voice held a rasp he didn't seem to notice.
He couldn't help it. What he had just seen was too similar, apart from the color of the flames.
Isaac's figure, his magic—both looked far too much like Grindelwald's!