Sachar: the father of Ahiam, one of David's elite warriors, known only through that one family connection
Sachar himself does nothing in the story. He turns up only as an identifying tag: "Ahiam son of Sachar the Hararite," one entry in the roster of David's finest fighting men known as the Thirty (1 Chronicles 11:26-47). Whatever made Sachar's own life notable, if anything did, has not survived; what survives is his son's name and his own.
The same roster appears again in 2 Samuel 23:24-39, but there the father is called Sharar rather than Sachar, and the hometown is given slightly differently as well. The two lists plainly describe the same thirty men, so this is one person, not two, caught in two slightly different spellings by the time the text reached us.
The name itself is built from the everyday Hebrew word for a wage, a hire, or a reward (שָׂכָר), exactly the word this entry's shared study traces from a shepherd's pay to the reward God promises the faithful. Naming a son after that word was ordinary practice: parents named children after debts owed, gifts given, or blessings hoped for, and a name built on "reward" fits comfortably alongside those patterns. Nothing in the text says why Sachar's parents chose it; it is simply the name he carried into the next generation, on his son.