-933- The only and absolute promise

"Senpai...?"

Mash squeezed out this sound from her pale lips.

"Are you awake, Mash?" Rozen continued holding Mash's hand, injecting magical energy into the Rune engraved on her arm to provide vitality.

Meanwhile, he involuntarily softened his voice.

"How do you feel?"

Rozen then showed a gentle smile to Mash, making her expression even more relaxed and reassured.

"What happened to me?"

Mash seemed a bit puzzled about her current situation, inquiring in this manner.

"You collapsed."

Rozen didn't conceal anything and answered straightforwardly.

With just this sentence, Mash roughly understood her situation.

"Is that so...?"

Mash lowered her eyelids, silent.

Seeing this, Rozen sighed and spoke with a slightly reproachful tone.

"You knew your body condition was abnormal for a long time, but you kept hiding it, right?"

Rozen made this accusation with great certainty.

It seemed that Mash's body had shown anomalies back in the Singularities, but due to her concealing it, she collapsed completely upon returning to Chaldea after completely relaxing her mind and body.

"Even when your body showed abnormalities, you still forced yourself to fight. Did you really think I wouldn't be angry?"

Rozen looked at Mash, sighed repeatedly, and spoke.

This made Mash, like a child who had done something wrong, lower her head while apologizing.

"I'm sorry, Senpai."

Mash apologized like this.

However...

"Hey, Senpai." Mash asked softly, "Can I endure it until we save human history together?"

Mash unexpectedly asked such a question.

Mash was undoubtedly the one who understood her own physical condition the best.

However, this young girl neither felt fear nor pain. She just seemed to anticipate and asked Rozen this way.

This made Rozen feel a pang in his heart, closing his eyes.

Undoubtedly, Mash had already accepted her fate.

The only thing this young girl hoped for was to fight with Rozen until the end, to save humanity, and to save the world where Rozen could continue to exist.

In this way, she could depart peacefully.

This idiot must be thinking like this, right?

The girl wanted to use her remaining time to restore the future of humanity, to restore the world where Rozen could continue to live.

As for herself, it was already beyond the scope of the girl's consideration.

"Even though Senpai now has more reliable Servants, I still want to fight with Senpai."

The girl, who used to be extremely afraid of battles, unexpectedly said so, even pleadingly.

As long as she could do this, the girl would be satisfied, thinking that her remaining less than a year of life had meaning.

This made Rozen subconsciously prepare to exert force while holding Mash's hand, but he desperately relaxed, fearing to harm this fragile girl.

Actually, if the goal was just to keep Mash alive, with Rozen's knowledge, there were many ways to achieve that.

For instance, Rozen could use Soul Magic, led by the "Taizan Fukun Ritual," to extract Mash's soul from her depleted body and transfer it to a new body that matched her soul, effectively resurrecting her.

Alternatively, Rozen could use Karyusai's secret arts to create a substance akin to artificial cells called "Seiryu," replacing Mash's depleted cells with lively ones, rejuvenating her.

Furthermore, Rozen could use Rune Magic, specifically the Primordial Rune, which possessed the power equivalent to a Noble Phantasm, capable of resurrecting people.

Moreover, Rozen could even form an absolute contract with Mash, turning her into pure records inscribed into his soul, ensuring her immortality.

In other words, Rozen could achieve what not even the Holy Grail could do – allowing Mash to continue living.

However, all these methods had their drawbacks.

Using the "Taizan Fukun Ritual" was out of the question.

This forbidden ritual was not only difficult to perform successfully, but even if Rozen managed it, finding a suitable new body for Mash was not easy. Additionally, any mistake during the ritual could harm Mash's soul, making Rozen hesitant to use it unless absolutely necessary.

Replacing all of Mash's cells with Seiryu was tantamount to a complete body reconstruction. This would likely turn Mash into something other than human, either an automaton like Yaya, Irori, and Komurasaki, or perhaps even an unknown monster. Rozen would never consider using such a method.

As for the resurrection Rune Magic, its limitations were significant.

The Rune had to be engraved on the user in advance and could only be activated at the moment when the heart stopped beating.

While it could bring someone back to life, it couldn't extend Mash's lifespan. Even if revived, she might die immediately afterward.

Furthermore, this magic had many restrictions – it required prior inscription, could only be triggered at the moment of cardiac arrest, and wasn't effective on bodies with severe injuries, like decapitation. Considering Mash's current situation, these restrictions made it unsuitable.

Regarding the absolute contract with Mash, it seemed like the best option. Given Mash's current feelings towards Rozen, forming such a contract would undoubtedly succeed.

However, there was still the issue previously mentioned.

To maintain a Servant's existence, Rozen needed to consume a significant amount of magical energy; otherwise, Mash would merely sleep within him.

Although Rozen's abilities had grown stronger, and he could use Mana to some extent, maintaining a Servant's existence would deplete Rozen's magical energy.

Fortunately, summoning Altera relied on the Holy Grail's provided magical energy, and Rozen only needed to maintain her existence for a short period.

However, over time, Altera would also have to return to Rozen's soul, awaiting his next summoning. For Rozen to summon again, he would have to bear the magical energy cost himself.

Without using his two aces, Rozen was unsure if he could do it.

Moreover, keeping Altera's existence, especially in combat or using magic, would shorten the available time. Considering these factors, there was a possibility that Altera might remain in Rozen's soul for an extended period.

This disadvantage didn't apply to Kinu and Gyokuto.

These two divine beings certainly consumed more magical energy than Altera and Mash. However, by relying on their manifested form on the talismans, without directly using their power, they could assist Rozen while consuming minimal magical energy.

Furthermore, they could provide feedback, accelerating Rozen's energy consumption and recovery.

So, unless they engaged directly in battle, the energy consumption wasn't a significant concern.

However, for Servants like Altera and Mash, it was a different story.

Given these circumstances, Rozen could only watch Mash weaken until he found a solution to the magical energy issue or had absolute certainty about saving her.

In this situation...

"Don't worry, trust me."

Rozen showed a relaxed smile to Mash.

"No matter what, I will definitely save you."

This was the only and absolute promise Rozen made.