Who is Hauptmann Wesreidau from The Forgotten Soldier and what is their importance?

Herr Hauptmann (Captain) Wesreidau is the company commander. Sajer serves under Wesreidau from the fall of 1943 until his death in the spring of 1944. Wesreidau is described as the consummate German officer, he is always in complete control of his emotional and mental state, and he is wholly devoted to the German cause. He is also said to be competent in military tactics and leadership, as well as an utterly fearless man. His men are devoted to him