Fake Boss?

'This creature—according to the system, it's definitely a boss monster, but... Something feels off about it compared to other boss monsters I've faced.'

From the moment he entered Polkentin's Secret Underwater Base, Izroth found that it differed from a normal dungeon, raid, or open environment. However, he was even more certain after encountering the Failed Chimera.

'Is it an open dungeon?'

Normal dungeons allowed up to six players who were in a party together to enter. Furthermore, even if another party entered the same dungeon, it would be impossible for them to run into players from other parties.

In RML, this was known as a closed-off environment—a place, in a way, disconnected from everything except what was within its confines.