Protagonist? No Way

Opening his eyes, Leon noticed the change in his environment, a place that was different from what he remembered appeared before his eyes, a huge luxurious hall full of unfamiliar stranger staring at him. What he quickly noticed is that every strangers seems to be young, with every single one of them wearing identical clothing which he was also now wearing.
Although full of confusion, in a short time frame Leon managed to kept his feeling to himself and quickly inferred that he was now in some sort of an educational institute with the number of available information: the room that seems to be a Lecture Hall, clothes that are uniform, a number of teenagers, as well as the adult with professional attire beside him.
"Leon, please introduce yourself." A soft voice beside him awakened him from his chaotic thought.
Without any more time and effective information, further speculation will only result in a guess with a high probability of errors as such Leon understood that what he needs to do now is to follow along and not appear differently before understanding the situation he was in.
"I am Leon." He spoke with a small voice.
This was one of Leon plan, the less he spoke the lesser the mistake. But, to appear reasonable, he planned to give the impression of being shy and nervous so that whatever speech mistake he made can be attributed to his nervousness caused by meeting a group of people that he did not recognize.
"Is that it...?" The person beside him that he assumed to be the teacher spoke after in a questioning tone.
"Um" Leon immediately replied with a smaller voice.
"Ok then, you can now go to your seat, it was empty seat on the top right corner besides the window"
After thanking the 'teacher', Leon walked to his seat and sat down noticing that there is still empty seat beside him. Ignoring the problem of his seatmate, he looked at the window by the side of his seat, seeing a lush forest and also a blurry reflection of his image with looks similar to what he remembered however, he was younger than what he recalled.
"Sure enough, there was a problem." Leon sighed in his heart while keeping his facial expression in check. Initially he thought of being pranked or kidnapped, but now seeing the younger version of himself he overturned his previous guess and thought of a seemingly impossible situation that he had only read in a novel, Transmigration.
As there is no other explaination he can think of, he will assume this guess as the truth before obtaining any additional information. Leon, in his past was someone un-remarkable, but he had the habits of reflecting on whatever information he had obtained, whether it was his or someone else experience and even the novels he had read was on the scope on what he would reflect on. This is what has led to his present character.
His flow of thought was once again interrupted by a cough.
"Attention all. Because there is a new classmate, I will re-introduce myself, I am Jean Astoria, your head teacher in 1G class. I am also responsible for teaching rune magic."
Magic!?
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Will be added and fixed later. This is just a simple draft.