It's definitely gained a significant fan base. The interesting characters and engaging plot have contributed to its popularity. Also, the way it combines romance and mystery elements appeals to a wide audience.
It's a story that typically involves elements like love, relationships, and perhaps some obstacles to love. Maybe it has a character who disrupts the normal flow of romantic relationships, which is what the 'killer' in the title might imply.
Well, without having read the 'Romantic Killer Novel', it's hard to say for sure. However, if we assume the basic premise of the title, there would likely be a main character who is the 'romantic killer'. This character might be someone who has had a bad experience with romance in the past and now wants to prevent others from experiencing it. Then there would be the other characters who are on the receiving end of the 'killing'. They could be a diverse group, including people from different backgrounds and personalities, all with their own ideas about love and relationships. And there may be some characters who are in between, not fully on the side of the 'killer' or the lovers, but rather trying to find a balance in this chaotic situation created by the 'romantic killer'.
Well, 'romantic killer light novel' might center around a protagonist who is thrown into unexpected romantic situations and has to deal with some sort of 'killer' aspect. This could be in the form of a rival who tries to'strike down' the budding romance or an internal struggle within the main character that acts like a 'killer' of their own romantic feelings. For example, the main character could be a person who has always been against the idea of love but then suddenly finds themselves in a world full of romantic possibilities and has to face their own preconceived notions which are like a 'killer' of their potential for love.