May I learn the age?
There is no confirmed information regarding Sanemi's years.
There are speculations that Sanemi is in his mid-thirties.
Considering the events, one can assume that Sanemi's years is around the age of 20-something.
There is discrepancy in the sources regarding Sanemi's age.
However, one thing is certain - Sanemi is an experienced and skilled individual.
Sanemi's commitment to his purpose remains steadfast, irrespective of his age.
In conclusion, the exact age of Sanemi may remain a mystery, but his skills, devotion, and commitment are undeniable.

Sanemi Shinazugawa Wind Pillar Kimetsu no Yaiba Demon