All things have yin and yang.
Just as there is a beginning, there is an end, and the struggle between spiritual power and magical power represents the fluctuations of life itself.
Like the positive and negative poles of an electric charge, spiritual power and magical power are both derived from the vitality of life. Whether it's the magical power of the mana or the spiritual energy of all things in the world, they are the same thing.
Therefore, whether it's humans or demons, exhausting spiritual power or magical power alone will not lead to death. They can slowly recover because losing yang still leaves yin, and losing yin still leaves yang. This doesn't mean that life force is completely depleted, so they won't die naturally, except when spiritual power and magical power are completely cut off, which is when life cannot be sustained because it's akin to non-existence.
However, although magical power and spiritual power are different paths to the same goal, their natures are opposite. To some extent, they can replace each other, but to better distinguish between them, people usually don't possess both simultaneously, as depleting both of them at the same time means death.
Therefore, individuals like shrine maidens, spiritual ability users, and spellcasters among humans use spiritual power, while demons, witches, and magus among other entities use magical power. The former practices Jujutsu, while the latter practices Magecraft. Even though spiritual power and magical power can to some extent replace each other, it's limited.
Rozen once used magical power instead of spiritual power to generate jutsuryoku in the world of Tokyo Ravens, and even absorbed spiritual energy from Hokuto and the Valkyries to replace magical power.
However, later, Rozen gained a vast knowledge of jujutsu and, with the help of the Mind's Eye reaching the divine realm, Rozen could effortlessly convert magical power within the body into spiritual power and vice versa.
After that, Rozen mostly used spiritual power when using jujutsu, increasing the power and scale of the jujutsu considerably and enabling the use of many jujutsu that were originally unusable.
As for divine energy, it's a type of spiritual energy, just like dragon aura, both are high-level spiritual energies.
Dragon aura is a very high-level spiritual energy, while divine energy is the highest level of spiritual energy.
Therefore, in the face of divine energy, ordinary magical power and spiritual power are generally difficult to resist. They can only be used by beings like gods or angels. It's also the strength of artifacts and war gods like the Lawbinding Shackles and the Mechanical Demon-Purging Assault Spear Mark Seven.
One cannot break them without equivalent divine energy, and the other can convert spiritual power into divine energy. Normal means are simply inadequate.
The so-called Mechanical Demon-Purging Assault Spear Mark Seven converts spiritual power into divine energy through the Divine Vibration Wave Drive Spell, artificially creating divine energy, amplifying the user's spiritual power, and ultimately eliminating the opponent's magical power, but it doesn't affect spiritual power.
This is because the Divine Vibration Wave Drive Spell on the Mechanical Demon-Purging Assault Spear Mark Seven doesn't discriminate between friend and foe. If it eliminates spiritual power as well, the user would face life-threatening issues, and would also become unable to use jujutsu.
That would be counterproductive.
Therefore, the Mechanical Demon-Purging Assault Spear Mark Seven of the Lion King Agency is specifically designed to deal with demonic forces, aiming to deal with magical power rather than eliminate spiritual power.
At this moment, Rozen has already converted the magical power within the body into pure spiritual power, using jujutsu against the enemy.
As a result, the Mechanical Demon-Purging Assault Spear Mark Seven of the Sword Shaman girl is naturally useless against Rozen.
"Well, after all, I'm not like Solomon who can nullify both magic and jujutsu."
Rozen murmured to himself with a voice only he could hear.
In the world of Chaldea, jujutsu is a mystery with local customs and significant associations with religious sects, so the Mage's Association doesn't acknowledge it and looks down upon it.
However, jujutsu and magic ultimately flow from the "root" as powers, taking different paths to the same goal.
And the ring of King Solomon can nullify all forms of magic, including jujutsu. Rozen's initial use of jujutsu against him already proved this.
Of course, King Solomon's ring is only aimed at formed spells, not magical power itself, so it's very different from the Mechanical Demon-Purging Assault Spear Mark Seven, and those ten rings can not only nullify magic but also control all magic, proving the wisdom of the sage. They cannot be compared.
However...
"Is it strange for you to use a weapon specifically designed to deal with demons against me?"
Rozen shrugged at the astonished girl.
"Although I'm also a mage and usually use magical power, I can also use jujutsu and spiritual power. Didn't the Lion King Agency know this and send you?"
"Or..."
Rozen cast his gaze on the girl, speaking indifferently.
"The Lion King Agency didn't send you to deal with me, but to deal with the seal inside me?"
In one sentence, the Sword Shaman girl couldn't hide her shock.
Clearly, Rozen guessed correctly.
"It seems I'm the same as Kojou after all."
Rozen spoke with a wry smile.
"You're the one sent by the Lion King Agency to monitor me, right?"
Exactly.
Even though the other party didn't say anything, just taking out the weapon, Rozen saw through and guessed the whole cause and effect of everything.
"Did the Lion King Agency command you to infiltrate Saikai Academy and secretly monitor me? Once there's any sign of the seal inside me being undone, immediately use that spear to kill me, to prevent the Fourth Primogenitor from devouring me and causing havoc in the world?"
Rozen's words, like a powerful force, exposed the girl's secrets.
"You... you..."
Rozen revealed and unravelled all the secrets, leaving the Sword Shaman girl utterly astonished.
However, there was one thing Rozen didn't know.
"What's your name?"
Rozen said coldly.
"Me... me?"
The girl was taken aback and subconsciously spoke.
"I... I'm Himeragi Yukina, third-year middle school student at Saikai Academy."
The girl revealed her name like that.
"Himeragi Yukina?" Rozen nodded suddenly, muttering, "No wonder Nagisa said your name sounds like a princess."
"Pr... Princess?" The girl immediately tilted her head in confusion.
She seemed unaware of the extent of her reputation in middle school.
Looking at her serious and meticulous appearance, it seems she still has some natural aspects.
"In any case, since you're my junior, I don't want to trouble you, but I also don't want to be under surveillance."
Rozen warned.
"You just tell your superiors that they don't need to bother with the seal on me. Focus on managing yourselves and look for any occurrences of magical crimes. Put your energy into that."
Leaving these words behind, Rozen prepared to turn around and leave once again.
"W... Wait!"
Naturally, the girl named Himeragi Yukina couldn't just watch Rozen leave, reaching out her hand to try to stop him.
Unfortunately, Rozen's figure had already been engulfed by the fluctuations of space, disappearing on the spot.
Only the girl was left, standing bewildered, at a loss for what to do.