Outside the ancient castle, the wind howled, heavy snowflakes falling thickly, coating the ground in a layer of ice. But Merlin felt no trace of the chill; rather, he sensed a lingering warmth, even taking off his thick wool coat to reveal only a thin shirt underneath.
Finally, with the Fireball spell model imprinted in his mind, Merlin was eager to test its power. After glancing around his room and deciding it was unsuitable for such a test, he donned his coat and ventured outside.
He recalled that the Wilson estate held a hidden underground chamber, spacious and secure—a place only Old Wilson, the butler, and Merlin himself knew of. It was the ideal location for testing the Fireball spell's power.
Following the memory, Merlin entered Old Wilson's study, pressing a specific brick on the wall. This action triggered the hidden mechanism for the underground passage.
With a slight clink, a segment of the study's wall slid apart, leaving a trail of dust in its wake, revealing a dark passage. Merlin grabbed a candleholder from Old Wilson's desk, lighting a few of the candles before entering.
The passage was dim and carried a stale, musty odor from disuse. Merlin descended the sloping stone steps that spiraled down for nearly a hundred meters. Along the walls, candleholders dotted the way, and he lit each one as he passed, transforming the once pitch-black tunnel into a well-lit corridor.
After a few minutes, the stairs ended, leading Merlin to a spacious underground chamber.
This hall served as the main area, but surrounding it were ten small rooms that stored an assortment of weapons, shields, and armor. Merlin remembered visiting this place a few times with Old Wilson in his youth, learning that it was modeled after a military stronghold. The underground chamber had been constructed as a refuge in times of crisis, stocked with enough provisions to sustain a small group for a full year.
Yet the years of peace in Blackwater City had rendered this place obsolete, making it the perfect space for Merlin's Fireball spell test.
Standing at the center of the underground hall, Merlin focused on the Fireball model in his mind. He could feel the fire elementals subtly infusing the model, which was constantly drawing energy, accumulating spell power over time.
According to Aita's notes, casting spells was simple. He needed only to stimulate the spell model with his mental energy, and the spell would manifest instantly.
"Fireball!"
Merlin spoke with intent, channeling his mental energy directly into the model. Instantly, a ball of intense heat appeared before him, floating less than a meter away. However, before he could control it properly, the fireball dissipated.
The spell failed because he hadn't yet mastered the control needed to maintain the fireball. Once a spell is cast, it demands the caster's mental energy to sustain and guide it.
Undeterred, Merlin quickly adjusted and summoned another fireball. This time, he held it steady with his mental energy, guiding it to float unsteadily through the air.
With a thud, the fireball crashed into the stone wall, its concentrated heat enough to make the solid surface tremble slightly, leaving a small scorch mark.
To further test its power, Merlin retrieved a suit of heavy armor from the storage rooms—standard for armored knights, designed to repel even the sharpest lances.
This time, Merlin rested for a while. His spell model had only accumulated enough energy for two fireball spells, and with each cast, it needed time to recharge.
Seeing the spell model slowly absorb fire elements once again, Merlin murmured, "Seems it's still limited in capacity, only able to cast two fireballs before needing to recover."
After about an hour, the model was ready, and Merlin cast the Fireball spell again, this time aiming it directly at the heavy armor.
The fireball struck the chest plate, instantly melting through the thick steel, leaving a fist-sized hole that smoldered with smoke. Merlin stared, astonished. He had anticipated the spell's potency, but seeing the armor—designed to withstand the mightiest of attacks—pierced so easily left him in awe.
Suddenly, something in his mental realm caught his attention: a faint gray bar had appeared alongside the spell model.
"When did this appear?"
Merlin frowned, certain that this bar hadn't existed when he first constructed the model. After close inspection, he noted that over half of the bar was now illuminated, with a small portion remaining gray.
After pondering it for a while without any answers, he chose to ignore it, focusing instead on familiarizing himself with the Fireball spell.
Casting another fireball, he mentally directed it at the heavy armor again.
This time, upon impact, the fireball exploded, scattering the armor into fragments.
This demonstrated the role of mental energy in spellcasting—not only guiding the spell but also modifying its effects. By controlling the explosion, Merlin could adapt the fireball's impact, either piercing a hard object or dispersing for greater area damage.
But casting spells was demanding, and after two fireballs, Merlin was drained of energy. He could only rest and wait for the model to recharge, as forcing it would risk collapse and potential harm.
During this break, he observed the bar in his mental realm again, which had now turned a bright red.
Intrigued, Merlin mentally probed it.
A soft hum echoed in his mind, and suddenly, the spell model surged, rapidly consuming his recently replenished energy. Before he could understand what was happening, an enormous fireball materialized in front of him, its unstable core hinting at imminent detonation.
This fireball was massive, easily three or four times the size of his previous ones.
Realizing the danger, Merlin quickly directed it toward the ground, avoiding himself in the blast zone.