Elihu is only mentioned in Chapters 32-37. He is not included among the three friends that come to comfort Job. In fact all that is told of Elihu is that he is a distant relative of Abraham through the line of Buz of the family of Abram (Genesis 22:20-21) and that he is incensed by the lack of acknowledgement of God Almighty's power in the views expressed by Job and his friends.
Elihu acts as an arbitrator, referee, pointing out that regardless of what circumstances you are in or why you are in that situation, God remains. He says:
God thunders marvelously with His voice; he does great things which we cannot comprehend.
As for the Almighty, we cannot find him: He is excellent in power, in judgment and abundant justice; he does not oppress (Job 37:5, 23).
And then Elihu disappears from the Job story and from the Bible. He makes one appearance and is then lost to history. Yet his role is essential. It is he who helps to direct the discussion away from self-aggrandizement and hollow rationalization, giving God the introduction to remind Job, the three friends and the readers who made everything including them.
There are Elihus all around us. Their names are different but they help us redirect our thoughts and lifestyles away from our egocentric self-importance and toward the One who made us.