At one point in the series, Hugo and his followers set out to kill Shun and everyone else during a camping trip. Given how determined and willing he was and how willing to kill everyone and cover it up, did everyone survive? The situation seemed dire, and it didn't seem entirely clear in the anime whether there were any casualties, since it went by so fast.
In the episode where this happens, after Filimøs/Ms. Oka resolves the situation, she says the following:
Shun, think you can go tend to Professor Oriza and Parton? ... It's okay, they're only slightly wounded.
It's easy to miss since he was introduced in this episode and really only appears in this episode, but Parton is the person Shun was talking to earlier, and the person who Hugo specifically attacked. So we can at least be assured that these two are alright. Filimøs's words generally give a positive outlook on the whole situation and seem to indicate that nobody died, but she doesn't really elaborate more than this. On the other hand, looking to the light novels spells things out more clearly.
In volume 2, page 188, in Chapter S5: Ruling Class, we get this:
Parton, Professor Oriza, and the others are all safe.
It seems to have been a close call, but thanks to Ms. Oka's intervention, no one was seriously injured.
All of Hugo's minions who'd attempted to attack people were captured.
So it seems there truly were no casualties. However, it's important to note that in the light novels, the earth dragon incident was actually part of the camping incident (and was actually brought there by one of Hugo's minions, though they lost control of it). In the anime, the earth dragon is instead affixed to the training incident where the students are practicing water magic. If I had to guess, this was done because they felt that Hugo needed further justification to hate Schlain/Shun enough to try and kill him (Yes, that's right: in the light novels, all Shun did to earn his wrath was douse his fire spell with some water magic. Furthermore, the books also go into detail that Shun tried to actively avoid dealing with Hugo, even back before they were reincarnated.). In the light novel's version of the earth dragon fight, Hugo's skills and stats have already been stripped by Filimøs, so of course he doesn't participate at all (though he is present), but other than that it isn't much different from the anime. And we get a wrap-up in the next chapter: From page 257, in Chapter S7: The Voice that Announces Ruination:
Wyrms and dragons...
Hearing that, I can't help but remember that incident.
Hugo's attempts to assassinate me, and the wyrm's attack on the school.
Several years have passed since then.
Although few were hurt in either assault, it was still a shock to the academy.
So, no mention of fatalities, and it seems that there weren't even that many injuries for either incident. As far as I can determine, it seems everyone was probably okay in both the anime and light novel continuities.