Please, I Really Didn't Want To Fall in Love With My Master!

Li Ran traversed to another world and became the Holy Son of a Demon Way Sect. The system has awakened, and the first task released is actually to fall in love? The Sect strictly forbids relationships between men and women. Li Ran took the risk of being expelled from the Sect and wrote a love letter to his junior sister, but it was sent to the master by mistake! — Description from novelcodex.org