In this story the totality of Saul’s reign is recorded.  It is significantly shorter than Saul’s story as narrated in 1 Samuel 9—31.  Plus, the story in 1 Chronicles 10 is uniformly negative.  It tells about Israel’s losing a battle to the Philistines, about the death of Saul’s three sons, and his being wounded by Philistine archers.  Trying to avoid humiliation, Saul orders his armor-bearer to kill him, something that the man is unable to do.  So, Saul kills himself (immediately afterwards, the armor-bearer kills himself).  The Philistines find the corpses of Saul and his sons; they desecrate Saul’s corpse by decapitation.  Eventually, Saul’s and his sons’ bodies are rescued and buried properly in Israelite territory.  1 Chronicles 11 begins the story of King David’s reign.