Manthri was born to Poomangalathu Kesavan and Kochikka, at Pandalam in Kerala, India.

Manthri studied painting from the Ravi Varma School of Arts, Mavelikkara.

The beauty of his cartoon character Pachu's wife earned a lot of praise from readers, and was mentioned by Professor M. Krishnan Nair in his weekly article Sahitya Varabhalam in Kalakaumudi weekly.

[1] His rash criticism through cartoons - in particular, a cartoon Kudanannakkan Aalilla which targeted the irregular appointment of Arabic teachers in schools from a particular community - irritated the then education minister C. H. Muhammed Koya.

Manthri was responsible for making the first animated film title in Malayalam cinema.