Adar and his older brother Abnar are Delilah's personal Rephaim bodyguards. As they are practically spitting images of one another, the only way to distinguish them is by their apparel, especially their hats. They are skilled in the use of most weapons, including clubs, spears, and sabres, though it is is in hand-to-hand combat that they really shine as warriors.
When Branan escorts Saphira back home to Jabneel from Hebron, he finds Abu and Adar waiting in ambush in Delilah's palace. As per Abu's orders, Adar attacks Branan by grabbing his neck and clamping off his windpipe. In a desperate move, Branan manages to undo his belt and use it to strike Adar in the eyes. Grabbing the bat the giant has just dropped, Branan clubs Adar over the head, knocking him unconscious. After Branan starts wrestling with Abnar again, Adar regains consciuosness and teams up with his brother to subdue Branan and drag him to Delilah's dungeon.
At the end of volume eight, Branan is given the opportunity for a re-match with the Rephaim brothers. As soon as Branan walks into the main room of Delilah's palace, Adar hurls a spear at Branan's head, just missing him. After Abnar gets his spear stuck in a pillar while fighting with Branan, Branan trips Adar and sends him head first into another pillar. Abnar regains consciousness and grabs Branan by the hair to punch him, but Zarah takes the Rephaim by surprise when she hits him across the head with her fighting staff.
It is presumed that Abnar and Adar perish with their mistress and Lord Pathrus in the collapse of Delilah's palace at the end of the final volume.
Although tall and strong, Adar and Abnar do not come off as very intelligent and have been described as having "the combined intellect of a sand tick." Indeed, they seem to suffer from a form of aphasia involving the inability to form complete sentences.
Adar and Abnar appear to treat everyone with cruelty, even each other. Abnar, for example, claims Adar leaps "like a pregnant water buffalo," while Adar feels his brother lands on his opponents "like a dainty butterfly."