He was the son of Nahwi bin Mansur bin Umar Walashma and younger brother of Haqq ad-Din I. Sabr ad-Din rallied his fellow Muslims in a counter-offensive in early 1332 against the Christian Ethiopians, he attacked christian garrisons, burned churches, enslaved the people and forced the clergy to convert to Islam.
[1] However, the chronicles of the King Amda Seyon I say he eventually got defeated in battle, Amde seyon then invaded a number of Islamic kingdoms, including Dawaro and Bale.
This brought an end to the independent kingdoms of Hadiya, Fatagar, Dawaro and Ifat.
[2] Sabr ad-Din was captured with his ally, King Haydara of Dawaro, and the two were imprisoned together.
The Emperor Amda Seyon appointed as his successor his brother, Jamal ad-Din I.