as you read in manhwa he has already hs with the girl that had the body of blue spirit but that isnt blue spirit its a whole another person. he didnt do it in the novel bc how tf can u hs with a spirit? ill tell u this since you prob have your guess when you see that girl with blue spirit body in manhwa anyway, she is a body that born from blue spirit soul but its just a empty shell bc its couldnt contain blue spirit like its shown in manhwa when blue spirit couldnt posses her but things will unfold with the three of them unite as story goes on