Petty Officer Second Class William-043 was a SPARTAN-II supersoldier. Because the SPARTAN-IIs' numbers had been thinned by the war, it seems that he developed a close working relationship with Frederic-104. He was one of the few Spartans to survive the catastrophic Fall of Reach, but he was later killed on Onyx by a Mgalekgolo pair, after valiantly engaging them in hand-to-hand combat. Complying with Office of Naval Intelligence Directive 930, William-043 was listed as MIA, continuing the tradition that Spartans never die.