Addar is a shaman appearing in The World Tree, the fifth part of Heroes Chronicles.
When Tarnum was sent by the Ancestors to save the World Tree, he sent letters to the five wisest shamans in the area, asking them what the World Tree was and how he could find it. The only thing they knew was that the World Tree was the source of all life, which was not enough to help him. But as he battled the necromancers and barbarians who wanted to destroy the World Tree, Tarnum learned that they followed someone called Vorr. When he asked the shamans who Vorr was, Addar could help him: Vorr was one of the Ancestors, who had taken the form of a war god worshipped by the barbarians of Krewlod. Driven to madness, Vorr decided to destroy the World Tree, the root of all life.
Addar travelled with Tarnum, giving him advice. Since Vorr drew his power from the worship of the barbarians, Addar told Tarnum that if they could get the leader of the barbarians, King Targor, to stop his worship, Vorr would lose his power. Tarnum figured out that since the war god was based on his own actions as the Barbarian Tyrant, showing King Targor the reality of his past would be enough to stop the Followers of Vorr. So they sought the Pendant of Total Recall, which could show Targor Tarnum's memories.
Sadly, Addar was an old man. The long marches became too much for his old body, and he died in his sleep. Tarnum buried him in the rich soil of the World Tree, with all the honors of the greatest barbarian warrior.