Now, Rozen possesses an immense knowledge of magecraft and a vast understanding of various magical techniques. His expertise in various spells is unparalleled globally. In terms of the quantity and variety of knowledge as well as the number of techniques, not even modern magus, let alone those from the Age of Gods, can surpass Rozen.
Therefore, Rozen is well aware of why his "Heroic Spirit Summoning" has been failing repeatedly.
One of the reasons, as Scáthach mentioned, lies in the catalyst issue. Without a catalyst, the "Heroic Spirit Summoning" will randomly summon the Servant with the best compatibility with the Master. Due to this randomness, practitioners cannot summon a specific Servant, and progressing gradually from weaker to stronger is impossible.
Thus, if the summoned Servant is too powerful, failure is inevitable.
Furthermore, the issue of magical power is indeed stringent, and Rozen has no solution.
Typically, summoning a Servant requires complex magical rituals, a mysterious process beyond human capability. Only with the assistance of the "Holy Grail" can such summoning become feasible. The summoning itself is a process conducted by the "Holy Grail." Otherwise, humans are incapable of conducting such large-scale rituals.
Chaldea, through various technological advancements, has systematized the summoning of Servants. However, the Heroic Spirit summoning system has remained imperfect, with only three successful cases so far. One Servant is missing, one can only become a pseudo-Servant, and only Da Vinci's summoning was successful, proving its immaturity.
This is why Rozen has consistently refrained from using Chaldea's Heroic Spirit summoning system to summon a second contracted Servant.
"Although Chaldea analyzed various 'Holy Grails' obtained from the Singularities and has gradually improved the Heroic Spirit summoning system, it would be even better if I could accomplish the summoning on my own."
Even though Rozen's self-summoning wouldn't benefit from Chaldea providing magical energy, and he would bear the entire magical energy consumption required for the Servant's manifestation, Rozen believes he can handle it given his current ability to harness vast magical energy. Before the transformation of "Mind's Eye," Rozen wouldn't have been confident in this, but now, with the ability to invoke the vast source of magical energy, he should be able to manage.
Rozen thought so, which is why he began delving into the "Heroic Spirit Summoning" rituals.
However, the result of this attempt left Rozen realizing...
"It's really much more difficult than I imagined."
Rozen felt truly helpless.
Apart from the problem of not being able to summon a specified Servant, which leads to a high degree of randomness and a low success rate, the main reason for failure is the issue of magical power.
Even with Rozen's extraordinary skills, mastering the "Heroic Spirit Summoning," a large-scale ritual beyond human capability, enabling a direct connection to the records on the "Throne of Heroes," is not enough. As Scáthach mentioned, summoning a Servant requires an extraordinary amount of magical power. A regular magus cannot afford it.
The spiritual foundation constituting a Servant requires an immense amount of magical power.
The spiritual core constituting a Servant requires an immense amount of magical power.
Maintaining a Servant's manifestation requires magical power.
Maintaining a Servant's strength also requires magical power.
In the Holy Grail War, aside from maintaining the magical energy required for the Servant's manifestation and providing the magical energy needed for battle, the Holy Grail handles all other aspects of consumption.
Although the burden cannot be considered small, it is not too great.
If it were within Chaldea, all the magical energy consumption could be provided by Chaldea, and the Master's magical energy could be used to enhance the Servant's strength.
Therefore, anyone with the qualifications of a Master would initially be summoned to Chaldea, and even ordinary people could participate in the task of laying the foundation of humanity. This illustrates the situation.
But if Rozen performs the "Heroic Spirit Summoning" himself, he must provide all the required magical energy.
In this case, even if he can channel the vast source of magical energy, summoning a Servant is still not a simple task.
Now, Rozen needs to see himself as a system similar to the "Holy Grail," completing all the engineering and work required for the summoning.
Saying it is simple, but how could the actual completion be simple?
Moreover, Rozen is currently conducting not just an ordinary summoning ritual.
This is precisely why Scáthach couldn't help but reveal that joyful look.
"Are you performing the ritual of 'Spirit Descent Ritual · Heroic Spirit Summoning' instead of the usual 'Heroic Spirit Summoning'?"
Scáthach unexpectedly spoke these words.
"Do you know about the Spirit Descent Ritual?"
Rozen was first surprised, then couldn't help but be astonished.
There was no way.
This was something not even Chaldea knew before.
"Originally, 'Heroic Spirit Summoning' is a grand magic meant for the decisive battle to save the human world."
Scáthach revealed this secret.
"Life and death are the basic forms of existence for anthropoids, and sometimes the world faces great disasters that hinder its own development. Therefore, when the world encounters a crisis, a grand magic to subdue the great disaster hindering the development of the anthropoid world emerges."
Its origin can be traced back to the Age of Gods and even the dawn of the world.
Among the countless records in the Clock Tower, it is similarly noted that 'Heroic Spirit Summoning' is meant to summon those who protect the continuation of humanity and allow them to manifest.
Initially, only seven Heroic Spirits existed for confronting great disasters. They stood atop all Heroic Spirits as messengers of the heavens selected by the "Root."
"For the convenience of humanity, attempting to reach the vortex where the 'Root' is located, a ritual named the 'Holy Grail War' was developed. That ritual was merely a summoning system derived from downgrading this type of magic."
Scáthach spoke as if she could penetrate the past and future, revealing such a fact.
"Perhaps Chaldea's summoning system is also the same, derived from the true 'Heroic Spirit Summoning'?"
Indeed.
If the true 'Heroic Spirit Summoning' is the origin magic to deal with the enemies of the world, then the modern 'Heroic Spirit Summoning' is the product derived from downgrading it for various purposes.
This applies to the ritual of the Holy Grail War.
This applies to battles protecting human principles.
Therefore, whether it is the summoning system of the Holy Grail War or Chaldea, both have their flaws to a certain extent. Not to mention summoning the origin's Seven Servant, even summoning a regular Heroic Spirit has significant restrictions.
Rozen has known this from the past.
Because...
"You are using the true 'Heroic Spirit Summoning' technique, one of the greatest mysteries in this world."
Scáthach looked directly at Rozen, making this assertion.
"So your summoning has consistently failed. Aside from the fact that the ritual's scale is too immense, the fundamental reason is its difficulty, which is fundamentally different from the usual 'Heroic Spirit Summoning.'"
This is a significant factor contributing to Rozen's continuous summoning failures.
"With the body of a mere human, trying to accomplish such a feat is not an easy task."
Scáthach said so, but her words were filled with excitement.
"Although you have failed, you have truly mastered the technique. In you, I can see the possibility of success. It seems I may have underestimated your talent. Perhaps in the field of summoning, your innate ability is already close to the divine."
Faced with such natural talent, Scáthach could hardly contain herself.
"It makes me want to train you into something truly exceptional."
Scáthach's eyes gleamed as she observed Rozen.