I doubt it's actually 4 different "factions" in an actual gameplay sense, rather than just lorewise. Seems to me that it may just refer to the 4 dukedoms that guilds can conquer. I interpret that black bubble to be that "evil" trying to take over the land, which may have cause the dukedoms to seize mindlessly slitting everyone else's throats for a moment and instead primarily focus on the threat that the black bubble poses to all of them.
If they were in an actual open war, it wouldn't make a lot of sense to crown a common emperor either. In that way, it really seems to be quite similar to the way it used to be in medieval times, where in some places, despite being part of 1 country with a common ruler, the different areas where still more or less autonomous states who sometimes waged war among each other.
I don't speak a single word of korean though, so if anyone can understand what they're saying he might be able to lighten this up a little.