Looks like Return of the SSS-Class Ranker.

This is the grand commander without the benefit of being a regressor—which also means this is the grand commander during her first life. Right now she's letting everyone walk over her and is fairly timid, but something happened that made her strong-willed enough to go through the apocalypse as many times as she did. She had a foundation in the academy before knowledge of the future, and I'm fairly certain that these events (and the instructor) helped build the foundation.

I think if Ronan was the one being bullied, she would have largely looked the other way as long as he didn't cause permanent injury. The issue here is that he's fighting for the assistant's sake—and despite her telling him not to, at that. If he earns the ire of all of the classmates and effectively declares that bullying her is a weakness for him, she'll just become a bigger target for others who want to get back at him but know they can't beat him.
A real-world comparison would be like if someone's dad or older sibling gets involved. Sometimes it works, but often it will just breed further resentment and escalate the bullying further. If she wants to stop being bullied, she needs to stand up for herself, not have Ronan do it for her. I can empathize with his emotions, but the instructor definitely made the right call here in stopping him, even if her turning a blind eye to the bullying itself is a lot more dubious and questionable.

Keep in mind, the instructor is the one who helped turn the Grand Commander into the person Ronan respected. But the thing is, it's not just in terms of power, but in terms of the respect she garnered from her subordinates, as well as her position. Being treated like that helps to develop humility, and then further pushes humility on those who look down on her once she gets strong enough to defeat them.
The instructor isn't going to coddle people. She let one of the best in the class get his ass kicked without stepping in for a moment, despite Ronan basically beating him senseless in a manner that could barely be called a "duel". If she allowed Ronan to beat up the rest of the class, though, that would actually do more harm to Ronan and the assistant than not.

You can tell a lot about a person through their actions. He was determined to fight despite how everyone else forfeited, but there wasn't any pre-battle trashtalk about how he would be the one to stop Roman in his place, or that he didn't believe the stories, and so on. Add to it the words of the crowd (which Roman is able to hear due to his increased senses) talking about how Fernando's fundamentals were great but this was as far as he'd go "with effort alone", it wouldn't be too hard for someone like Roman to get an idea of his mindset and motivations. He may not know outright if he's right, or if Fernando will go along with what he says, but there's no harm in probing and offering; if Fernando responds belligerently, Roman can just beat him up afterwards.

Flashy and good chapter overall, but I can't help but to feel there's some wasted potential here. So far, Rokan basically overpowers each and every thing he comes across, so there's very little doubt whether he's going to win or not even when the odds get super stacked against him. It would have been more compelling if he narrowly lost, or even had a draw, and he ended up developing a positive relationship-slash-rivalry with Jaros. Jaros seemed to be a battle maniac himself, and the story could've been better with him still in it rather than tossed away for some instant gratification chapters.

Interestingly enough, I think the defense could have potentially argued self-defense or emotional response on the basis of perceived stalking and prior abuse. She clearly made an attempt to leave the household and get away from him, and yet he deliberately showed up at her place of work to confront her. I'm not sure if it would fly during this time period or in a country where filial piety is so strong, though.

I'm usually a bit wary about reading .5 chapters, but I'm grateful I decided to read this one. It's nice to see how despite how much of an adult she acts and the weight of what she's attempting to accomplish, she still has childish pursuits and a pure, non-financial dream.

What, you don't?

It's not just you; I was also confused at the beginning. Seo Minhye in the present looks pretty similar to Park SooYoung of the past, just a little more slender and younger but not by too much. Add to it the whole fashionable actress concept and the comfortable manner she started talking to MC with, and I say it's pretty normal to get them mixed up.

He's accomplishing a few things with this. First of all, the set up of the dungeon is completely unreasonable even before MC started messing with it. It goes above and beyond what would be considered normal or even sane to get a high score. The other incidents involving the school can be covered up as mere accidents with the proper press coverage, but something like this is very obviously intentional, showcasing the principal's twisted mindset and unfairness towards the students. Furthermore, there are more people who will watch something for entertainment than they would read the news, so this is actually broadcasting this out to them as well.
Second, and perhaps most importantly in this case, is that he's putting himself forward as a banner to rally those who hate the principal to contact and work with him. A lot of people hate the principal, but they're unwilling to do anything because they fear retaliation or don't quite have enough to accomplish it. Get enough people invested, though, and they'll be able to pull him down and stain him with the mud he tried so desperately to avoid. The only thing that's protected him so far was his connections and influence, and that can only go so far when enough people start causing problems.