The Four Incomplete Heroes
The fact that the summoned Hero wasn't just one, but four, threw not only the Demon King's forces into chaos but the human side as well. It was an utterly irregular situation with no precedent in history.
The empire's mages conducted a sort of physical examination on the summoned children to investigate this bizarre phenomenon. The inspection covered aptitude for each class, mana capacity, personality, and qualities as a Hero.
Soon, the empire's mages arrived at a satisfactory conclusion. These four were all Heroes, yet at the same time, incomplete ones. To be precise, the four children each possessed one of the qualities that a single Hero should have, divided among them. Ares had justice. Mari had wisdom. Luna had bravery. Sera had mercy. They were all Heroes, but only when united did they form a complete one.
The empire ultimately recognized all four as Heroes and decided to train each according to their aptitudes. Ares became a Knight. Knights were the shields protecting the empire and the sturdy pillars of any party. Leading with their ironclad defense, knights stood at the forefront, blocking enemy attacks. A well-trained knight's offensive power was no joke either—piles of monster corpses felled by knights' swords formed veritable mountains.
It was a class that suited the kind yet intolerant-of-injustice Ares perfectly. Mari became a Archmage. Archmages specialized in offensive magic. Though physically inferior, their powerful spells could overturn anything. Especially their wide-area attacks that annihilated hordes of monsters at once—those were the exclusive domain of archmages. For Mari, already hailed as a genius girl in her previous world, it was a perfect fit.
Luna became a Martial Artist. A rare class specialized in close-quarters combat, martial artists fought barehanded, relying on their honed bodies, unique agility, and raw power to tear enemies apart. Finding a master was tough even in the empire due to its scarcity, but for Luna, a martial prodigy from the start, it was ideal. Sera became a Saintess. Among priestly classes, Saint and Saintess were the pinnacle, recognized only by innate holy power. Saintesses mastered all healing magic and were adept in useful buffs. They even wielded potent offensive spells against monsters and undead. This all-around class suited the grumbly yet caring Sera to a tee.
Though none was a perfect Hero individually, with proper training and synergy, they could surpass a single Hero. On the flip side, any discord in the party could crumble them like a sandcastle. Of course, seeing their current harmony, no one thought it'd break easily.
"Ares! Mari!"
As Ares and Mari walked side by side down the palace corridor after finishing the day's training, a familiar voice called from ahead. Ares smiled and greeted them.
"Sera. Good work today. Luna too."
"Y-yeah. You two as well."
"Sera sis is still so full of energy even now."
"Seriously... Mari always has to say something..."
"..."
The four exchanged greetings, happy to see each other. With all duties done, rest was all that remained. Everything had felt alien and awkward when they first arrived, but time had soothed them bit by bit. A week had passed since coming to this world, and they were growing accustomed to life here.
It was partly their adaptability, but mostly thanks to the empire's enthusiastic support. Over a thousand years, the empire had summoned Heroes sixteen times—a rare ritual once a generation or so, essential for defeating the Demon King. Knowing this, they spared no effort in treating the Heroes well.
The empire supported them materially and mentally to ease their isekai adjustment, without forcing anything. Summoned Heroes naturally cooperated due to their nature, so no coercion was needed. Their confusion lasted only the first day; afterward, they smoothly followed the empire's program, training to become true Heroes.
"Sigh... Still, it's a shame we can only train together during joint classes."
Sera sighed as she spoke. As she said, with different class aptitudes, they trained separately under different masters. They shared history and common knowledge lessons, but were mostly apart.
"Yeah. Kinda like pre-college life, though—not bad."
"Oh, thinking of it that way... Ares, you're so positive. Amazing."
"Not amazing enough for that."
Ares empathized and comforted her, brightening Sera's mood into a smile as she praised him. Maybe irked by the sight, Mari grinned mischievously.
"Sera sis just misses not seeing Ares oppa, right?"
"W-what? N-no...! It's not like that...!"
Sera's face flushed crimson at Mari's words. Ares just scratched his cheek awkwardly watching her fluster.
"I-it's really not...! Hng, Luna...!"
"Calm down, Sera. Mari's just teasing."
Luna, ever composed, soothed her in her signature flat tone.
"Mari, don't tease Sera like that."
"Yes, oppa. Sorry, Sera sis."
"Ugh... I always feel like it's not a real apology."
But she couldn't snap at her crush's little sister. Sera swallowed her frustration inwardly—though her face gave it all away, drawing wry smiles from the other three.
Teased or not, Sera was adored by her friends.
"By the way, still no master for you, Luna?"
Sera changed the subject, and Luna nodded.
"Yeah. Heard it's a beastkin...? They wander a lot, hard to contact. Some discrimination too."
"Ah... Yeah, like the princess mentioned in common knowledge class."
Unlike their old world, this one had non-human sapients: elves, orcs, beastkin, even high demons like the Demon King. The empire that summoned them was human-only; other races got unequal treatment. A millennium after the racial wars, outright slavery was rare, but hierarchies persisted.
Luna's prospective master seemed special among beastkin, spared overt discrimination, but...
"...I'm fine as is. Just keep training like always since childhood."
"True, Luna was always strong... Even stronger since coming here."
The four had gained superhuman power upon arrival. Basic physical stats improved, aptitude-related parameters surged, and above all, their mana vessels—the hallmark of Heroes—grew at absurd rates.
The key difference from locals was mana vessel size. Natives had fixed innate capacity; Heroes could expand theirs endlessly. Fully grown, a Hero wielded hundreds of times a normal person's mana, manifesting it against monsters.
Humans alone couldn't beat the Demon King due to its bottomless mana from reincarnation-accumulated cores, nearly infinite.
"How strong is the Demon King, anyway?"
Sera asked idly, and Ares replied.
"Dunno... But unbeatable for us now. Princess said even fighting his minions overwhelmed locals."
"Ugh, can we really win against that? I know nothing about fighting..."
Sera looked anxious; Mari sighed.
"Sera sis worries too much. Demon King hasn't revived yet, and by then we'll be way stronger. Past Heroes always won."
"But... why'd four of us come...?"
Sera's unease lingered.
"It's okay, Sera. I'll protect you."
"Luna..."
Sera beamed at the reliable Luna's words—more trustworthy than most men. Watching, Mari's mischief returned.
"Heh... You two are always close. Guess I'll ask oppa to protect me then."
"Of course, Mari. I'll keep you safe."
"Hehe. Thanks, oppa."
Mari linked arms with Ares demonstratively, sticking her tongue out at Sera. Knowing Sera's crush, her intent was clear. True to form, Sera's reaction drew wry smiles from the trio.