Duke had indeed learned an immense amount of spells on the spot, and logically, he didn't even need to take the spell manuals back with him. However, seeing the librarian's stern gaze, as if to say, 'if you don't respect magic, I'll give you a hard time next time,' Duke relented.
Moreover, Duke discovered a rather serious issue for himself: the limits of the system sprite—it turned out, the system sprite was a product of the scientific side of things.
For magic that could be explained by science, the system sprite was godlike.
For example, with the previous ice and fire magic, the system sprite could not only help Duke instantly learn the magic, but also immediately derive a plethora of advanced magical talents, enhancing the power of the magic in all aspects.
For some categories that felt unscientific or were unfamiliar to Duke, like the enchantment spell "Hypnosis," the system deemed it 'unidentifiable.' And the prophecy spell "Comprehend Languages," which allowed users to understand spoken language but not read or write it, the system's feedback was 'violates principles of translation studies, unidentifiable.'
Most notably, with the necromancy school, the system directly informed Duke that it was 'lacking unknown necessary conditions' and thus unusable.
Duke could only take a pile of spell manuals back to the dormitory arranged for him by the academy and slowly digest them on his own. Basically, he had memorized all the spells and could use them if needed, but they lacked that instant mastery factor.
Duke knew that he was being demanding.
The librarian explicitly told him that the various techniques and advanced magical talents for casting spells would be taught by mentors to their students. Outsiders wouldn't be able to learn the essence of it. At most, they could learn some basic techniques from certain mentors during public lectures for all academy students.
To learn, one could do so, but it required equivalent exchange!
The problem was that Duke had previously refused Medivh, and besides Norton, no other mentor would likely be willing to share magical techniques with him.
The crucial point was that Duke discovered the overall magical level of the academy was not high. Aside from Medivh, there were only two Morningstar mages left in the entire academy, and no magic books above level 5 could be found in the academy library.
To learn more advanced magic, one would either have to go to Dalaran or... to Karazhan. Yes, Karazhan, which was under the control of the Burning Legion's big shot, Sargeras, and Medivh's old lair. As a Guardian and the son and heir of the previous Guardian, Aegwynn, Medivh had a private mage tower in Karazhan.
South of Elwynn Forest was the Duskwood, and the southeastern part of Duskwood was the Deadwind Pass, with Karazhan located within it.
It was effectively Medivh's territory, and outsiders were prohibited from entering.
If Duke had been willing to be Medivh's disciple earlier, he could have entered, but he would have also been at risk of being devoured, bones and all.
"The limit of Stormwind's Royal Academy of Magic is here... How can I break through this limit?"
As Duke was feeling somewhat disheartened, there was a knock on the dormitory door.
"Who is it?"
"Duke, it's me—Daniel, and Itana is here too."
"Come in!" Duke, buried in a pile of books, extended his right hand, and arcane power gently circulated within his magical circuit as he performed a small trick.
Alteration spell "Open/Close."
The door lock, ten meters away, was opened by Duke's spell.
"Click." The door opened, and both Daniel and Itana were somewhat surprised to see Duke sitting so far away, as he should have been the one to open the door.
Daniel craned his thick neck, seemingly trying to see if there was anyone else behind the door, or if Duke had hired a servant.
...
"Daniel, it's just an Open/Close spell," Itana whispered.
Daniel chuckled, scratched his head, and stepped in. Due to Daniel's enormous size, he occupied two-thirds of the hallway, forcing Itana to follow him like a subordinate.
Raising his head from the pile of books, Duke noticed Daniel's relieved expression.
"What's up?"
"Nothing, I just realized that you have a human side too, Duke. I thought you wouldn't need to learn anything and would directly ascend to the level of Guardian Medivh."
Itana couldn't help but laugh.
Duke could only shrug helplessly: "Alright, did you come to see me about Master Norton's matter?"
The two nodded simultaneously: "Master Norton had just finished his research, and as soon as he found out you were back, he notified us to come and tell you that 'the notes have been translated.'"
"Thank you," Duke smiled. He glanced at the robes the two were wearing, and his smile grew brighter. On Daniel's chest were two small book symbols, while Itana had three. In the Royal Academy of Magic, these were the signs of junior and intermediate apprentices.
The number of apprentices simply reflected talent. Only the number of book symbols indicated an apprentice's status. Of course, some would remain as high-level apprentices for a long time.
Under Duke's gaze, Itana felt somewhat embarrassed: "We can't compare to you."
"No, no, since we all came from the Northshire Abbey, we should help each other more. I'll go to Master Norton first, and we can catch up later."
Not only the honest Daniel, but even Itana's face couldn't hide the joy.
It couldn't be helped; Duke had been in the spotlight lately. First, he killed Hogger, then he singlehandedly opened a pearl trade route. Even their master had hinted at them to communicate more with Duke.
And so, they accompanied Duke to the north side of the academy, where Mage Norton's private laboratory was located.
Only mages of the Morning Star level or higher were allowed to build their own mage towers within the academy grounds. As a Sky Mage, old Norton merely had a detached house with an independent courtyard as his laboratory.
As if sensing Duke's arrival, the courtyard gate automatically opened. The steps that should have led to the main entrance on the first floor rose abruptly, transforming into a staircase leading directly to the third floor.
As soon as Duke stepped on the first stair, he suddenly heard a voice: "Hold on tight."
The next second, the entire staircase, like an escalator, carried Duke up to the third floor.
At the end of the stairs was a circular window that spiraled open just as Duke was about to reach it. Through the bright light, Duke saw Norton, sitting in a lounge chair and examining his notes with a monocle-like magnifying lens.
"You're here?"
"I'm here."
"I heard you gained quite a bit in Westfall."
"Do you need research funds, Master Norton? I can..."
Norton waved his hand: "I'm old and have lost my motivation. I don't need those worldly things anymore."
At this moment, Duke felt an unprecedented sense of... twilight on the old man.
What had happened to the old man?
Mage Norton looked up at Duke and suddenly smiled: "It's nothing. I just saw my own limit and the potential in you. Even if I'm not qualified to be your mentor, I hope you can accept my legacy."
...