MC Male

(if only I can find a bl like this story(〒﹏〒). Yes I'm asking for no fuck Bl)
>Comedy/fantasy/magic/magical beasts'/reincarnation-isekai?/two travelers/holy priest (?) MC/
Mc was transported into the romantic fantasy novel his younger sister was reading, not as the male lead but as the second male lead. Moreover he is fated to go into war in the future and die in the male lead’s place.So he made up his mind to not go anywhere near the main characters and stay healthy until he can go back home.