Who is Hals from The Forgotten Soldier and what is their importance?

Hals is Sajer's closest friend. He is slightly older than Sajer, and he is described as physically large and strong. Sajer notes that for the most part, Hals is a "teddy bear", though the occasional lack of sufficient food can send him into violent rages. Hals is a cheerful, happy, and optimistic man, who loves to eat, and who is always hungry.