After a brief playful moment, Caleb proactively brought up his fight with Tetsuya Hoda. Rias listened attentively, her expression thoughtful.
"From what you described, Tetsuya Hoda must have used a bloodline ability called Berserk Mode."
Rias pulled Caleb into a hug again, delighted. "As expected of the man I favor! After only a few days of training, you were able to directly defeat a low-tier Youkai who activated his Berserk Mode."
Caleb blushed slightly. While he did defeat Tetsuya Hoda, calling it "directly"... was a bit of an exaggeration. If Tetsuya Hoda had been determined to run away, Caleb wouldn't have been able to catch him. Flexibility and speed are not the same concept, and the speed of a 'Berserk' Tetsuya Hoda far exceeded Caleb's.
"Rias-senpai..."
"Call me President. Everyone here calls me that."
It wasn't a big deal, so Caleb readily agreed.
"President, you just said I won by beating someone above my rank. Wasn't Tetsuya Hoda a freshman like me?"
Seeing Caleb call her President, Rias felt as if she had already successfully made him her familiar. In a great mood, she patiently explained the detailed power hierarchy of the supernatural world to Caleb.
"No, the time of enrollment has nothing to do with power level." Rias explained, "It's like how the term 'Low-Class Devil' doesn't necessarily refer to a power level."
"Aren't Low-Class Devils, Middle-Class Devils... ranked by strength?" Caleb was even more confused.
"Not entirely. All pure-blood Devils are considered Low-Class Devils upon birth." Rias pointed to herself. "Someone like me and Sona, blood descendants of the 72 Pillars of the Demon Lords, are considered High-Class Devils from birth."
"But can you say we have the strength of High-Class Devils from birth?"
Caleb shook his head, starting to understand.
"Then how exactly are the ranks determined?"
"Leaving aside the names Low, Middle, and High-Class Devil, as those are unique Devil titles—similar to old human noble titles." Rias pulled Caleb down to sit beside her and spoke seriously, "The power classification for all other races is much more detailed and precise."
"Ordinary people who step onto the path of cultivation and master magic power can be classified as Rank D..."
With Rias's detailed explanation, Caleb finally gained a clear understanding of his current strength: Peak Rank D, but not yet Rank C.
To reach Rank C, one needed to master at least one magic spell or skill. Regardless of the rank, attribute, or function, mastering it qualified one as Rank C. Of course, Beginner Magic Power Extraction didn't count; successfully mastering and using it was the absolute minimum to enter Rank D. Similarly, individuals like Yukina Sasaki, who possessed special talents but couldn't master magic power, wouldn't even be considered Rank D.
For example, a person without special talents who mastered magic power could easily defeat one who had talents but lacked magic power. The magic user only needed a low-level illusion spell to render the talent user helpless.
However, the distinction between Rank D and Rank C was rather arbitrary, simply because there were too many individuals at this level, and there was no qualitative leap in power. More importantly, most other races automatically possess Rank B strength upon reaching adulthood.
Rank B: Typical Low-Class Devils, Lower-ranking Fallen Angels, and two-winged Angels belong to this rank. Ordinary humans need to cultivate magic power to permeate their entire bodies to reach this level, such as famous enlightened monks or Church bishops.
It's also worth noting that not everyone in this world cultivates Magic Power. There are also practitioners of Aura, Cursed Power, Spiritual Power... a variety of different energies. Though they sound different, they all originate from absorbing special energy from the Aether, but with different focuses, naturally leading to different methods of use and thus different names. This latter part was Caleb's own speculation based on his vague memories.
Rias only explained enough to give him a basic understanding, so he wouldn't be completely flustered when encountering enemies.
The higher ranks are more straightforward.
Rank A: Exemplified by human Rank A Warriors, Middle-ranking Sorcerers, Middle-Class Devils, Mid-ranking Fallen Angels, and four-winged Angels.
Rank S: Naturally includes High-Class Devils, High-ranking Fallen Angels, six-winged Angels, High-ranking Sorcerers, and Church Rank S Warriors.
Rias didn't go beyond this, leaving out the power equivalent of Ultimate-Class Devils or the Demon Lords. Rias didn't say, and Caleb didn't ask. It wasn't too late to consider those ranks after he reached Rank S.
Tetsuya Hoda had mastered the innate Berserk Mode skill, which qualified him as Rank C, which is why Rias said Caleb defeated an opponent above his rank.
"Why doesn't the Student Council's file contain these power rankings, and why didn't it have the information that Tetsuya Hoda could use Berserk Mode?" Caleb was a novice without common knowledge of the supernatural world, so he asked directly without embarrassment.
Rias smiled slightly. "Of course, it's impossible to have that level of detail. If the statistics were that precise, who would want to enroll at Kuoh Academy?"
"Because of the Great War many years ago, this is now a barely peaceful time, but friction between the races has never stopped." Rias continued, "To confirm a person's rank, they need to be completely honest, which is very difficult."
"For example, Tetsuya Hoda would never expose a trump card like the Berserk ability during testing. Collecting such sensitive intelligence not only invites resentment from the students but also cannot guarantee accuracy."
Caleb nodded knowingly. "Indeed. No wonder the file President gave me was so general."
"President, do you have any idea what the strength of the third-years Daisuke Oida and Mika Yasuhiki might be?"
Rias, of course, knew; she had paid attention to the other two on the list.
"Are you planning to go try your luck with those two as well?" Rias looked at Caleb with interest. "Third-year students are at least Rank C; anyone who couldn't reach that level would have been expelled long ago."
"It's only Rank C. I'll be Rank C too once I learn a magic spell..." Caleb rubbed his cheek and shamelessly asked, "President, look... how about you teach me a couple?"
"Magic isn't as easy to learn as you think, even the simplest low-level spells..." As Rias spoke, magic power gathered in her hand, and a ball of orange-red flame appeared, hovering obediently in the air. "For example, the Fireball Spell. To cast it instantly without chanting, and with precise control, an ordinary person would need at least a month."
Caleb curiously watched the small fire orb in Rias's hand, tempted to reach out and touch it. The scorching air warned him against acting rashly. Resisting the urge to court disaster, Caleb asked, "An ordinary person needs a month. How long did it take you, President?"
Rias smiled confidently. "Not bad. I mastered it in three days."
"That's amazing, President! You have incredible talent for magic!"
Rias was quite pleased with Caleb's compliment. She was, after all, only seventeen, a girl in the bloom of youth. It was just that her figure was more developed than a girl her age typically should be... The traits of maturity, calmness, and strength were forced upon her as the next head of the Gremory family; they were necessary traits to project. Only in front of her familiars could Rias truly return to being a seventeen-year-old beautiful girl.