The Substitution of the Shield Hero

Mirellia was sitting at her bedside table, Filo tucked securely against her chest.

A few hours had passed since Naofumi had boldly declared his intentions. And at the same time, a few hours had passed since the wave began.

At first, Mirellia was concerned...

And then she noticed a strange sight.

Peering out the window, she noticed that the bloody sky was blanketed in a few black dots.

And while she was confused at first... Mirellia remembered the past incidents where attackers had seemingly rushed towards Naofumi.

"Ah." Mirellia gazed down at Filo's sleeping form and murmured, "So that is why Naofumi appeared so blase."

The mechanics were completely unclear.

Mirellia knew of no magic that could forcibly redirect such attacks at such a scale... nor send the attackers such a distance towards the redirected target.

The legends of the Shield Hero from the distant past indicated he could divert attacks towards him with the power of the Legendary Shield...

But Naofumi clearly lacked that.

Perhaps if he had some other Legendary Weapon-

Mirellia froze. "...No. It couldn't be. Could it?"

Legendary Weapons... they were said to be ancient spirits that manifested in the form of weapons. Some said they were the core of the world itself, its will bound in the form of an armament to resist the interdimensional threats of the waves.

Because of that, they possessed incredible powers and abilities that defied both belief and commonsense.

Even so, they fell short of the power necessary to repel the waves.

Because the world itself could not resist the waves directly, it condensed its might into the form of a weapon for a hero to face off against the waves directly, summoning a user that it believed could utilize the full potential of its might.

...At least, according to the ancient records Mirellia had been reading recently.

But if that was the case...

"...What if the world IS powerful enough to directly resist a wave?" Mirellia murmured.

The world they lived in... it was the byproduct of four failed worlds. The presence of four Legendary Weapons... Three now, but once four.

That indicated that four separate worlds had desperately banded together to gather the strength necessary to resist the waves. Even then, clearly, it was far from sufficient.

But what if a world existed that WAS sufficient? One where its inhabitants either possessed enough power or technology that interdimensional invasions didn't need the world to step in? Where the inhabitants of the planet relied on their own power to defend against threats?

In that case...

...What would happen if the brightest from a world like that was summoned-

No.

Stolen?

Mirellia subconsciously held Filo a bit tighter, finding comfort in the fluffy Filorial chick.

"...A world like that wouldn't take it lightly," Mirellia murmured. "No, it would definitely not take it lying down."

The series of messages came to mind again. The one that appeared when the Legendary Shield vanished forever.

===

[The Covenant was shattered.]

[The Hero was betrayed.]

[The World has been judged.]

[From this point forward, the Legendary Shield will no longer exist in this world.]

===

Mirellia let out a sharp gasp as she realized the truth of it. "...The Legendary Shield stole a soul from a world with a will that was unfathomably more powerful than it. As a compromise, and out of courtesy, the world allowed it due to the circumstances. But after the agreement was broken..."

It was all too clear now.

A stolen soul. And one that was clearly important, considering everything that Naofumi had done since arriving in this world.

But Naofumi's world had allowed it. Likely due to the desperate plea of the Shield Spirit. Still, it hadn't simply left Naofumi... Or rather, the man calling himself Naofumi, to go alone without any safety nets.

And when Melromarc treated Naofumi the way it did... when his world deemed theirs as not fit for salvation...

It killed the Shield Spirit.

And in the process...

It opened up space for Naofumi to fill with his own abilities, knowledge, and skills.

Mirellia stared at Filo again, letting her shaking heart calm down with the sight of the cute pink Filorial chick.

When she had composed herself, Mirellia let out a soft sigh. "What misfortune... and what fortune we have received."

The world was found lacking.

Naofumi's world went out of its way to remove one of the pillars propping it up. A spiteful act to hasten its destruction.

But Naofumi... that ridiculous man.

Despite not caring about the world, despite having no true ties, despite clearly being able to leave whenever he wished...

Instead of letting the world be destroyed, he decided to make it useful instead.

And as a byproduct of that, the world would be saved.

Mirellia let out a helpless laugh. "Should I be grateful that such a man found something in us worth keeping? Or annoyed that we are surviving due to a whim?"

"Fi..." Filo grumbled a bit and snuggled closer to Mirellia's chest.

Mirellia sighed and then calmly turned her gaze towards the crimson and fractured sky.

It was a sign of calamity. Proof that a force beyond the world's reckoning had come to use it as a plaything in a greater game than they conceived.

But amidst that crimson sky, there was the full moon.

And a full moon that now had a clear spot of green. No doubt the result of Naofumi's latest grand project.

Mirellia couldn't help but smile at that. "I suppose as frustrating as that man is, there's no denying his brilliance..."

===

The northern reaches of Melromarc.

After running around Libertas trying and failing to find Bahamut, both Lia and Sylvia decided to just let it be.

Considering that Bahamut was Naofumi's son, he would eventually do something ridiculous that would make it clear where he was.

When that happened, Lia and Sylvia would head over there. But until then, they decided to get some exercise in.

And by 'they,' it was mostly Lia.

Lia watched with interest as False Mercy instantly vaporized the obsidian skeleton warrior that had been rushing towards her. "Hm..." She eyed the pristine golden blade that Naofumi had gifted her to torment her previous owner and said, "Is this because Naofumi-dono made this blade with such a powerful healing ability?"

Sylvia flicked her wrist, slashing with her rapier at a shadowy kraken in the distance. Crimson lightning crackled from the heavens, turning the seamonster into ash. And after that, she looked at Lia and said, "Our Master does have a habit of creating things with unintended consequences... and not sleeping."

Lia sighed. "Yes... we need to figure out how to force Naofumi-dono to sleep. Maybe we have Mina and Nina convince him?"

Sylvia casually scorched a shadowy lizardman into ash with another blast of crimson lightning. Then she said, "We did that last time, remember? And now he made sure to have Rishia tuck them into bed."

"Right..." Lia furrowed her brow, casually splitting apart a horde of undead pirates. As she watched them turn to ash from being struck with False Mercy, Lia said, "Maybe we should just pin him down ourselves?"

"He would just use it as an excuse to stay awake then and say something about not being able to sleep due to how awkward it is."

Lia paused and her ears drooped. "...True."

Sylvia hummed. "I suppose we could try to use guilt? It worked when we were smaller."

Lia's crimson eyes lit up. "That's true! If we tell him how concerned we really are..."

"He should listen." Sylvia nodded. "Especially if we use the father card."

Lia tilted her head, casually swatting aside what looked like an undead pirate captain. "Father card?"

"Master says we're like his daughters, does he not? In that case... we can say that we do not wish for our father to die due to a careless mistake from not sleeping."

Lia gasped. "Sylvia! You're a genius!"

Sylvia looked smug. "Thank you. I've been thinking about it a lot." Her fox ears drooped and she said, "I really am worried about Master... His judgment isn't the best when sleep deprived."

Lia giggled. "I remember! Like how he didn't notice our clothes were too small until they were WAY too small."

Sylvia chuckled. "Yes. And like how he kept making houses and hotsprings for us to use as shelter in the forest... which means there are now quite a few of those just laying around unoccupied."

Lia's eyes widened. "That's true! That's so true! I forgot!" She giggled again and said, "Do you think people will come across them and believe it's the work of fairies?"

"Or elves. Those mystical beings seem ripe for the subject of conversation when it comes to mysterious constructions in the wilderness."

Lia and Sylvia bantered a bit more as they casually strolled across the battlefield, destroying the stragglers from the wave that weren't flung upwards into the sky from attacking Libertas.

And speaking of monsters being flung upwards...

Sylvia watched another goblin get launched upwards after lunging at a house, clearly intending to break it. As she followed its form slowly turning into a tiny dot, she noticed the full moon had changed a bit. "...Lia." She tilted her head and said, "Is it me? Or is the moon now... Green?"

Lia looked up and gasped. "It IS green!" She giggled and said, "Naofumi-dono...! You're not supposed to change the color of the moon because you don't like it!"

Sylvia giggled and said, "Well, Master does whatever he... wants...?" She suddenly trailed off, staring in the distance.

Lia noticed and followed Sylvia's gaze. "Hm? What's wrong, Sylvia... Huh?" She blinked and tilted her head. "...Why is there a lady who looks like you?"

Sylvia didn't respond. Instead, she just stared at the woman Lia was talking about. At the woman who had made her stop in her tracks.

Pristine skin that looked carved from white jade. Snowy white hair that looked like threads of moonlight. Violet eyes that were like pure amethysts. Fluffy white fox ears... and a face too beautiful to be real.

One that looked like Sylvia's.

In fact, if they stood side by side, Sylvia was sure they could be mistaken as sisters. The only difference was that Sylvia's build was slimmer due to her training while that woman's was voluptuous, like a court courtesan's.

But-

"Yàn'er?"

Sylvia's heart shook.

A name that had been hollowed out of her by the trauma she endured.

A voice that she had prayed to hear again and again but never did.

A trembling smile and open arms that Sylvia still caught glimpses of in her dreams.

And a name that was the only thing Sylvia clung to after she was saved by her Master.

Su Daji.

And...

"...Mother."

...Sylvia's mother.