What Earth hadn't discovered yet was that the worlds that were the dungeons were all located on the second level of the Realm, while Earth and thousands of other planets with intelligent life forms were situated on the third level of the Realm.
Amongst them were the skrivaloks that were soon going to attack Earth by controlling the direction of the dungeon gates.
Keeping this information to himself for now, Ivan continued to listen to Teacher May. For the following minutes, they talked about how dungeons were classified. When a dungeon appeared, the dungeon gate would have a specific colour.
A dungeon with a blue dungeon gate was considered the weakest among other dungeons and was classified as grade 1. These types of dungeons can be attempted by warriors at the first and second level, of course, they had to do it in groups.
Next after the blue dungeon gate was the yellow dungeon gate, these types of dungeons had monsters of considerable strength and could only be dealt with by Level 3 warriors and above. Anyone weaker would be doing themselves good by avoiding such dungeons.
In total, there were only three Grades of dungeons. The strongest being the dungeons with Red gates, only those at the Level 4 and 5 warrior ranks were capable of clearing such dungeons.
Again, Ivan smiled slightly in his seat. Teacher May's information wasn't incorrect, it was just incomplete.
There weren't just 3 Grades of dungeons, there were actually seven in total. After those with Red dungeon gates, there was gold, black, white, and the strongest of all, the colourless dungeon gate. This dungeon gate looked as clear as still water but didn't show any reflection, it was like staring into an empty mirror.
But Earth was currently too weak to attract these types of dungeons, which was why they thought there were only 3 Grades.
"Ivan Castellan, is it that my teaching is too boring for you that you had to zone out while I'm still talking?"
At this moment, Teacher May's voice rang in Ivan's ears, pulling him back from his thoughts. His eyes flashed but didn't wander around to avoid it truly looking like he had zoned out, he noticed that the other students were looking at him but he didn't panic or make sudden movements.
Instead, Ivan stood up in a composed manner and asked calmly.
"My apologies, I was just thinking about something after listening to you talk about the grades of dungeons."
Teacher May's eyes narrowed, Ivan's actions were smooth but she was certain that he hadn't been paying attention.
"Is that so, why don't you share with us what you were thinking about?" She asked with a slight grin, hoping to catch Ivan.
No matter how quick-witted a student was, it would be impossible for them not to show any flaws when faced with this situation.
But instead of getting flustered, Ivan calmly presented a question.
"Is it possible for dungeon gates to suddenly change colours?"
Cases of dungeon-grade suddenly rising were very rare on Earth so many people didn't know about this, but Ivan had encountered lots of them in the past.
A glint flashed past May's eyes when she heard Ivan's question. In the end, she told him to sit down and pay more attention while she proceeded to answer his question. The rest of the students were also eagerly waiting for her to answer, Ivan's question had piqued their interest.
"While it's very rare, there are certain instances when the grade of a dungeon would suddenly increase. This is sometimes caused by a stronger creature forcing its way into the dungeon, or a general forced evolution of the dungeon." She explained.
Gasps could be heard from the students after learning that a dungeon could grow stronger as well after appearing. A student raised her hand at this point, signifying that she had a question to ask.
Teacher May gave a nod and the student stood up.
"What if people had already gone instead, and how much stronger can a dungeon grow?" The young girl asked, a slightly scared look on her face.
"Yes, a dungeon upgrade can occur even with people inside. As for how strong it can get, a blue dungeon can become a red dungeon under special circumstances." Teacher May replied calmly.
The entire classroom went deathly silent, so that one could hear if a needle fell. All the students had pale faces after they heard their teacher's response.
If they were to enter a blue dungeon and it suddenly turned to a red one, didn't that mean they were dead for sure?!
In the corner, Ivan stared at his classmates and couldn't help but smile. Recalling his first experience in such a dungeon. He had been peacefully training in a gold dungeon when it suddenly rose to a white one, luckily, he was still in the first region when he noticed the change and immediately turned back.
He had equally been spooked at that time despite being what humans would call a Level 7 warrior, so he couldn't blame these kids for having a similar reaction.
"Alright, that's enough. A dungeon suddenly changing colour is very rare; it only happens once in ten years. Don't get too worked up about it.
Next, let's talk about the regions inside a dungeon." Teacher May voiced out, forcing the students to return to their focus.
"Every dungeon has three regions and each region is usually occupied by different types of beasts, so be prepared to fight different creatures in a single dungeon.
In the case where the entire dungeon is populated by a single species, you'll notice the strength gap between each region upon making contact.
Now, the first region…"
Teacher May went on to elaborate.
Simply speaking, the first region was the space that one would arrive upon entering the dungeon. The creatures in the first region weren't too strong and were close to the benchmark of the dungeon's grade.
So if it was a blue dungeon, the creatures in the first region were mostly only as strong as Level 1 warrior rank humans.
While still in the first region, it was still possible for people to leave without clearing the dungeon. This was why it was advisable to rest in the first region for a bit after killing all the beasts in it.
The second region was at the heart of the dungeon and creatures here weren't significantly stronger than the ones in the first region. At best, they would only be a few sub-stages stronger.
Reaching the second region, one would no longer be able to leave the dungeon if they wanted and would need to clear the dungeon to exit it.
The third region was the end of the dungeon and had the strongest beasts, creatures of this level can be an entire level stronger than the ones in the second region.
To make it worse, the beasts in the third region always had a boss monster commanding them. This made it difficult to deal with them since the creatures were capable of carrying out coordinated attacks.
In this situation, it was very advisable to kill off the boss first and do so quickly. After clearing the third region, another dungeon gate would appear and one could leave the dungeon; they actually didn't need to walk all the way back.
"As for how big each of the regions is, it depends on the size of the dungeon. Some regions can go from being a few hundred meters large to the size of a whole city or even larger."