Primordial Demons

During the time Nyarlom was fighting Tsukiko, in the cave where Leonard Tranor had sealed the Primordial Demons, Shin who was also known to Ren as the fourth hero was out of breath. For the past three days, he has fought the escaping Primordial Demons from the hole on the seal. It has been thousands of years since their last attempt to escape, but unlike that time the current Primordial Demons were growing more powerful by the second. Not only that, but the hole on the seal was growing.

Some of the Primordial Demons were actually able to get past Shin. He had tried his best and had killed a few dozens of Primordial Demons, but their numbers were just increasing instead of decreasing. 

Even though the current Primordial Demons were not at full power, they were still a major threat to the current humans. Letting even a few of them out was already quite bad.