Of course, traveling through time and space was actually a very simple matter, if only considering the Space-Time of the Ninja World.
In the Ninja World, Sora had already become unparalleled, with no equal in the past or future.
What he was interested in were other dimensions.
Picking up that Otsutsuki artifact, Sora entered seclusion once more.
A few days later.
Sora, still in seclusion, opened his eyes.
A sense of connection from another dimension came over him!
Simultaneously, some extremely familiar incantations sounded.
"Fill. Fill. Fill. Fill. Fill."
"Let each be turned over five times, simply breaking asunder the fulfilled time."
"Let silver and steel be the essence. Let stone and the archduke of contracts be the foundation. Let my great master be the ancestor. Raise a wall, against the wind that shall fall. Close the four cardinal gates. Come out from the crown. Rotate the three-branched road reaching the Kingdom."
"I shall declare here. Your body shall serve under me. My fate shall be with your sword. Submit to the beckoning of the Holy Grail. If you will submit to this will and this reason... then answer."
"An oath shall be sworn here!"
"I shall attain all virtues of all of Heaven. I shall have dominion over all evils of all of Hell!"
"From the Seventh Heaven, attended to by three great words of power, come forth from the ring of restraint, Protector of the Balance!"
Hearing the incantation in his ear, Sora frowned slightly.
"The first other world I found is actually the Nasuverse?"
"However, I suppose it's a fitting specialty."
Sora smiled. After all, his current situation was having a great quantity of power, but lacking things like rules.
Coincidentally, in the Nasuverse, pure power wasn't that strong either… the strongest aspect was Mystery.
Mystery, of course, was also a type of rule.
Going to the Nasuverse would allow Sora to fill in his gaps regarding rules.
"Go as a Servant? That's acceptable..." Sora nodded.
"After all, that's the usual practice. Since it's the norm, it's better not to break it."
"Well then, let's go!"
Sora focused on that vague, grand voice.
The next moment, a pulling sensation came.
However, compared to Sora's immense mass, that pulling sensation was a bit weak.
Thus, Sora understood once more.
"I see. This passage is too narrow… I can't cross over myself. So it has to be an avatar?"
"Well then, fine. An avatar it is!"
Manipulating the Reiatsu around him, Sora transmitted it towards that pulling force.
Then, using the Greater Grail, or rather the spiritual foundation provided by the Grail system, as a basis, Sora constructed a duplicate.
After checking the duplicate to ensure there were no problems, Sora let go.
Simultaneously, his consciousness also traveled to the other world.
The final summoning call came.
"Answer me!"
Meanwhile, amidst a flash of brilliant light, Sora stepped out of the summoning circle.
Feeling the knowledge bestowed by the Holy Grail, Sora spoke: "Servant, Assassin, answering the summons. I ask of you, are you my Master?"
As he spoke, Sora looked at the man before him, dressed in priestly garb.
"That's right, I am your Master!" Kotomine Kirei said in a calm tone.
"Servant, what is your true name?" Kirei asked.
"True name..." Looking at Kirei, Sora didn't really want to answer him.
Because even if he answered, Kirei wouldn't know who he was, since he was a Servant from another world.
Also, this Master was too problematic, Kirei, the person who finds joy in others' suffering, anyone who knows, knows.
So, after thinking it over, Sora decided to answer him and then find an opportunity to break away.
"My name is Yuki Sora. I am a Servant from another world," Sora replied. "Strictly speaking, you can think of me as a Ninja or a samurai. Anything a Ninja or samurai can do, I can do."
"Is that so..." Hearing Sora's words, Kirei's eyes flickered. "A Ninja from another world..."
"But a Ninja..." Kirei thought for a moment, suspecting that Sora's strength might not be high.
In other words, had he drawn a bad lot?
Still, it didn't matter.
Kirei didn't have any particular goal for participating in this Holy Grail War anyway.
So Kirei said to Sora:
"Alright then, Assassin. Rest for a while. I'll arrange things for you later."
With that, Kirei walked out, going to the basement where Tohsaka Tokiomi was.
"Sensei!" Kirei greeted respectfully.
"Kirei, is your summoning complete?" Tokiomi asked.
"Yes, Sensei. It is Assassin," Kirei replied.
"Assassin," Tokiomi pondered. "Hassan-i-Sabbah. It feels like a bad lot. Assassins have never had much combat ability."
"Still, it doesn't matter, because I already have victory in my grasp!"
"We don't need combat strength. Assassin will be fine for gathering intelligence."