Sir Eltek is the father of Ferlin Eltek and Miso Eltek, and the head of the Eltek Family.
For a long time he had a complicated relationship with his eldest son Ferlin due to the fact that his son cut ties with him and Miso, over the disaproval of marriage between Ferlin and Irene.  Eventually, his wife sent a letter to his son demonstrating that he had forgiven him. Later, when Ferlin when came to his house to learn more about the Eltek Family and their relation to Agatha, they saw each other again he decides to follow his son to Border Town to deliver Agatha's belongings. 
While on Border Town, he stayed in Ferlin and Irene's house and eventually became closer to the couple. Then, he revelead that he stil wants Ferlin to be the head of the family, since Miso isn't the right one to be his successor. 
Due to Miso's eventual betrayal against Roland, he sees himself obligated to get involved in the fight for the throne against his second son Miso.  Eventually, he becomes a supporter of Roland and enters the Adviser Department which eventually gets integrated into the First Army.  Due to it, he occasionally appears giving his opinions on war meetings.