King Ahaziah fell through the lattice of his upper chamber and was badly injured. Instead of praying to the God of Israel, he sent messengers to consult the Fly, the god of Ekron. That decision cost him his life.
God intercepted the mission. He appeared to Elijah and told him to meet the messengers on the road with a single question: does Israel not have a God of its own, that the king sends to a foreign deity? Then tell him he will not recover from this injury. The messengers turned around immediately. When Ahaziah asked why they returned so quickly, they described the man who stopped them: hairy, wearing a leather belt. Ahaziah knew at once it was Elijah.
So the king sent a captain with fifty soldiers to bring Elijah in. They found him sitting on top of a hill. The captain commanded him to come down. Elijah's response was simple and terrifying: if I am a true prophet, let fire fall from heaven and destroy you and your men. Fire fell. All fifty-one were consumed.
Ahaziah sent a second captain with another fifty. Same demand, same threat. Same fire from heaven, same result. Every man destroyed.
The third captain was a wise man with a gentle disposition. He climbed the hill and did not command. He pleaded. He acknowledged that the previous captains had perished, and that he and his men had come not willingly but under royal orders. He asked for mercy. Elijah accepted this, came down, and followed him to the king.
Standing before Ahaziah, Elijah delivered God's verdict directly: because you despised your own God and sought answers from a foreign idol, you will die of this injury. And shortly after, Ahaziah did die, having reigned only two years. His brother Jehoram inherited the throne, since Ahaziah left no children.
As for Elijah himself, Josephus records something extraordinary. Not long after, Elijah disappeared from among men. No one witnessed his death. Josephus compares him to Enoch, who vanished before the great flood. The sacred books, he says, record that both simply disappeared, and nobody knew that they died.