I don't really ship anyone in this series but I'm guessing its because they're the main characters shown on the cover, and because yandere ships are fun to read when they're fictional.
i love yul, but whoever ships him with sian is honestly rlly gross. he's literally a psychopath with an obsession with her. he needs help and they shouldn't get together (⌒▽⌒)
For the people who ship Sian with phychopathic ex.............ummmm why.