Containment
The pale white fog became thicker as Nero descended, reducing the visibility to only a few metres ahead. As if that was not enough, the effective radius of Aether Pulse was also reduced drastically, making it so that he needed to use the card every few steps.
Considering their previous experience, it was odd that they faced no curses yet, but that could also be an effect of the fog. Despite its seeming harmlessness, it was by far the most dangerous thing here.
By the time they reached the third level, they faced no challenge, but instead of feeling relieved, Nero only felt more concerned. There were a few things causing such concern.
Visibility was obviously a big part of it, but another was that there were no more stairs heading downward after the third level. Yet when he was taking the test to gain access for the lower levels, he was certain he recalled mention of a fourth level. Lastly, it was because he felt no cursed energy at all.