He was the eldest son of Lorenz of Werle and Matilda of Werle-Goldberg (d before 17 December 1402). After his father"s death in 1393 or 1394, he initially ruled Werle-Güstrow alone, but probably together with his brother John VII from 11 December 1395 and from 1 May 1401 with his brother William.
From 1 May 1418, the brothers called themselves Princes of Wenden after they found evidence of royal lineage in the chronicles of Bishop Otto of Havelberg. Baltasar died on 5 April 1421 and was buried in the Cathedral in Güstrow. He was first married on 18 October 1397 to Euphemia (d 16 October 1417), daughter of Duke Magnus I of Mecklenburg.
Heilwig later married Dietrich of Oldenburg.
Number children of Balthasar are known.
