if you read the epilogues it turns into a harem but the novel "ending" is not a harem and you don't have to read the epilogues. there are like 60 chapters of epilogues/after stories but it is not relevant to the main story.
It's definitely a harem if you're just talking about the genre. It has all the tropes of a harem but at least there being a bunch of beautiful girls and few hot bachelors makes sense in this verse being that apparently a lot of the men died in the last few battles. But as the person above states it also LITERALLY turns into a harem in the side stories. Looks like they cut a lot of the harem type scenes in the webtoon though so I believe anyone that doesn't care for harem scenes can enjoy the webtoon MAYBE. After all the illustrator did change and they may decide to add that stuff in soooo.....
can someone that read the novel tell me if this is a harem or not（/TДT)/