Saving a world.
Shiro have been extremely familiar with this act. He had saved a couple of worlds, starting from the one he inhabited during his third life. After that were the mission worlds. From the small incident on Aincrad up to Madoka's world-destroying event—he had prevented all of those. He even saved others from tragic endings such as Shinji's destined fate as well as the sacrifices that Emiya Shirou has to make.
During these times, he had been saving others. He is a hero in their eyes. However, Shiro does not view himself as such. How could he be worthy of that title when he could not even save his own world? All this time, he had been saving them for his 'self-interest', namely: for the good of his students and then the mission rewards.
Truly, the burden of not being to save his world bore down on him for a long time. It is to the point that his two incarnations, Fenrir and Magus, prepared countless plans and simulations for the day they could return.
'Today is the day.'
Starting now, he would become a hero.
*****
"I didnot expect to see you here."
"...You too."
The two faction leaders 'greeted' each other. Enterprise (Ash) and Observer Zero met each other several times during their confrontation. What is surprising is that the latter exists in every timeline, compiling each data and variables before sending it to their database shared across timelines.
"He told me about you." Enterprise said. "I hope you remain true to your words."
"I will. We does not have difference in our goals. It's just that our way of attaining it is different."
"By sacrificing dozens of timelines to your experimentations, was it?"
"It had to be done."
Ironically, both Ashes and Sirens paid something to seek for salvation. The former lost a part of themselves while the latter did not care enough about several timelines' destruction.
"Culling the leviathans won't simply save our world." Observer Zero tried to grasp for more information.
"Didn't he tell you? Decreasing their numbers inside this space would reduce their connection with our world."
"It wouldn't do much. At most, it would spawn more of the—" She paused as she realized something. "Unless..."
"Its core is dealt with."
The destroyed world parasitized their world to continue living. It siphoned its life through the leviathans' slaughter and destruction of it. It can be seen that the destroyed world is the hive mind while the leviathans are its workers. It would not do much if leviathans were killed as the hive mind would simply spawn another batch.
But what if the hive mind itself is dealt with?
Theoretically—
"It would no longer spawn and... our world is saved."
Then again, it is extremely absurd! Impossible, even!
"Is this his plan?!"
For the first time in a while, Observer Zero lost her plan.
"This is impossible, Ash. He might be the Commander that both Doctor Anzeel and Aosta admired, but even he could not do the impossible. Only omnipotent gods could accomplish this."
One has to know that the leviathans are already dangerous by themselves. If one traced it to their core, they would receive the ire of an entire world. No matter how dead it is, a world is still a world. Only the omnipotent god could fix this problem!
"Omnipotent gods, you say?" Enterprise smiled mysteriously. "Shiro is nothing short of such."
In the end, Observer Zero complied as she saw how much Enterprise trusted him. She knew how she made her rational decisions, more so when she acquired an affliction as a META.
*****
"What a pleasant welcome."
Using the connection established between my world and the destroyed world, Shiro easily passed through both worlds.
"I can also use everything right now."
First of all, he cast a <Creator> domain around him. This invalidated every single attacks that the destroyed world had employed. The various rewards that he received in Altair's world bestowed him with three omnipotent attributes as well as elevated his two stats to <Creator> rank. It is not wrong to say that Shiro is a bonafide <Creator> rank entity.
He has enough capabilities to go against a world as he had demonstrated on his fight against 500 servants in the past as Magus. With three main authorities as well as several sub-authorities, he is extremely strong.
It is also the reason why his world rejected him previously. The child that it had once nurtured died, only to return as a omnipotent god?
"This should do."
Shiro spread his domain outwardly. From here, he saw various mirages of the destroyed world. Advanced technological civilization experimented on their world to seek for the further path, only to destroy it as a result. The leviathans were the ones that served as their "warships", which is why it was often deployed by its [Will].
"...Hm?"
By scouring the remnants information that this world has, he discovered something.
"Its inhabitants were taken away?"
Moments before its destruction, several gods took away most of its inhabitants. Interestingly, there is a "system" in this world akin to the one Shiro has. Everyone could access it and gain power step-by-step. Once they reached the peak, they could even aim to become a god.
As time passed, his domain almost encroached every corner of this world. Its struggles became useless in the face of an unrestrained <Creator>. Though, Shiro knew that his "struggle" to keep his identity until the world accepted him was necessary. Without the world's acceptance, he would not be able to use the connection that it has to this world. He would either be forced to defend himself or retaliate against his world's power, which will then lead to its destruction due to that clash.
Simply, he is just reaping the benefits of his hard work.
Snap-!
Snap-!
Snap-!
He sensed their connection weakening as the destroyed world's hold over his home world disappeared. It is the result of the two factions as well as Akagi and Nimi obliterating the leviathans present in the Temporal Gap—the place where timelines converge. It is the black sea that is used by META ships to travel between timelines.
On his right hand, he materialized his black sword. It is his trusty partner that accompanied him throughout from his third life up to now. It bore [Destruction] itself.
On the top of his head, a crown adorned with jewels appeared. The glimmer that they brought emanated the aura of wisdom that Shiro has as a magus. He is the embodiment of [Wisdom] itself.
A bright glint went past his eyes as he "saw through" the essence of this world.
"A mutated world."
Finally, he saw its history. Turns out, this world was actually a part of a big world. Once it was destroyed, it separated and became a "remnant" which drifted on space and time. Unfortunately, it latched to his world. Its actions of forming a connection with it is purely instinctive—a struggle that has to be done in order to live. With that, a [Will] was born.
"..."
Upon discovering something, Shiro did not hesitate to create a time clone. It held all of his power, but it would not last for long.
"I will check something. Ask Akagi or Nimi for help if something bad happens."
Shiro saw the time clone nod.
'This... A <Creator>?'
Upon reading this world's history, he felt the involvement of a <Creator> rank entity. She is similar to nature as Angra Mainyu as he felt the origin of all evils within her.
As expected, he was sensed by her despite the gap between time. It is one of a Creator's characteristic—to not be affected by time. In order to completely settle this issue, he would be diving at that exact time.
Shiro became a gray fog as he dove into the river of time. Moments later, it dispersed, returning the scenery to normal. Only the overwhelming domain of a creator could be sensed in this place.