The present study has been conducted among the Tagin tribe of Arunachal Pradesh which is one of the major tribes of the State. The objective of the study is to examine the Indigenous Knowledge System of the tribe to understand the current issues that humans are facing today largely relating to ecology through folklore. The prime focus of the study revolves around Abo - Tanii: a forefather figure whose doings have a lot to do with the current scenario of the tribe and the world as a whole. It is an attempt to bring the story of Abo - Tanii and the Tagin into the realm of Folkloristic Anthropology and Socio-cultural anthropology as a whole. The study will give a new dimension to the discipline of Anthropology in understanding tribal communities and their Indigenous Knowledge System relating to ecology. It will also bring forth the Tagin tribe to notice as the tribe is hardly even recognized by its country due to morphological and cultural differences.