Teaching Twilight Sparkle magic was a very pleasant task for Aurora. She was a very clever pony who could always infer other things from one fact, and Aurora was also getting a taste of the sweetness of reviewing the old to learn the new.
Sunset Shimmer had no interest in being a tutor, but she would quietly do her own things on the side.
Perhaps she treated this place as a geomantic treasure land where she could both avoid The Grand Princess's nagging and study in peace.
Occasionally, Aurora would pretend she didn't remember a certain magic spell and ask Sunset Shimmer for help, trying to get her to integrate into the session.
Although Sunset Shimmer saw through Aurora's intention at a glance, she would still temporarily stop what she was doing, provide the answer for Aurora, and then immediately go back to her own work, completely in a state of being uninvolved yet not out of place.
At least Aurora's method worked, even if not entirely.
Even Twilight Sparkle could see that Sunset Shimmer did not seem like a pony who was easy to get along with, but with Aurora teaching her so enthusiastically, she was already content.
Thinking about how the representatives of the two future elements of harmony had this kind of dynamic when they were young, Aurora felt a headache coming on.
However, there was nothing to be done about it; it would take many seasons of stories before they grew up enough to stand on their own.
Aurora and Sunset Shimmer would go to report their recent study progress to Celestia at a fixed time every week, and it just so happened to be today. Tomorrow was the day of Twilight Sparkle's entrance exam, and thinking about how she was about to see the legendary Sonic Rainboom, Aurora couldn't help but curl the corners of her mouth.
However, Sunset Shimmer's mood was not as wonderful as Aurora's.
Thinking about having to report her study insights to Celestia later, she felt some resistance, because every time, Celestia would require them to make more friends.
She only hoped that their recent tutoring of Twilight Sparkle would be enough to fool The Grand Princess.
"Flying Light, why do you think Princess Celestia is always obsessed with having us make more friends?"
Clearly their magic levels were improving day by day, so why spend time on useless socializing?
Sunset Shimmer could never figure this out; she felt that communicating with ponies whose strength was inferior to her own was a complete waste of time.
Sunset Shimmer once thought that Aurora's thoughts were the same as her own; after all, when it came to learning magic, she was even more driven than herself.
But seeing her teaching Twilight Sparkle magic so attentively these past two days, she felt it wasn't quite like that.
"Because friendship is magic."
Aurora directly used the title of the entire series to answer Sunset Shimmer's question.
"You're joking, right? Don't tell me you actually believe in that stuff."
However, the current Sunset Shimmer was just a pure power-seeker, believing that power would only be possessed by the aloof strong. To make her imagine that a group of ponies just making friends could obtain the strongest power in the world, she would probably have to eat a Rainbow Cannon herself.
Thus, Aurora thought of Sunset Shimmer from Equestria Girls, with a broken expression on her face, crawling out of a pit in a sorry state, and couldn't help but feel heartache and a sigh in her heart.
She was originally as proud and high-spirited as she was now, but because of a single wrong thought, she left her homeland and ended up with her dignity swept away, in a state of extreme humbleness.
Even though she was reborn like a phoenix after understanding the true meaning of friendship, Aurora still couldn't bear to watch Sunset Shimmer go through that low point again.
"I believe, I believe very much. Doesn't Star Swirl the Bearded have a book researching the Magic of Friendship?"
"But that book was never finished, it has no conclusion! I think Star Swirl the Bearded must have also felt it was complete nonsense and chose to give up."
Sunset Shimmer had also read that unfinished book by Star Swirl the Bearded. This was something that even the greatest wizard had failed to accomplish; it wouldn't be an exaggeration to say that the Magic of Friendship didn't exist at all.
"It wasn't finished because Star Swirl wasn't good enough, not because the magic wasn't."
"...I really can't believe I'm hearing this from you, a fan of Star Swirl the Bearded."
Sunset Shimmer showed an expression of disbelief, feeling that Aurora had become a bit obsessed, actually saying such things for a magic that didn't exist, when she usually always took Star Swirl the Bearded as a role model.