[Gender-bender + competition for the female lead + lighthearted, lively tone, minimal leveling, minimal monster-fighting, no System.]
After repeatedly being suspected of organizing fights and trying to disturb the peace of her sect, she was forcibly assigned a mission to enter the mortal world and exorcise demons.
Shiyue, a former evil cultivator in her past life who is now trying hard to maintain her saintly persona, had her plans to lie low and make a good life for herself in the sect ruined.
But she gradually discovers that the methods of an evil cultivator work incredibly well in the mortal world...
The book is very nice.