Neroon was a member of the Minbari Warrior Caste from the Star Riders clan. During the storied Earth-Minbari War, Neroon fought against the humans and eventually became Alit (second in command) of a Minbari warship under the command of Shai Alit Branmer, a Minbari of mixed Religious- and Warrior-caste parentage, who was so incensed by what he perceived as the humans' unprovoked murder of Dukhat, the leader of the Grey Council, that he defied tradition and took up his father's caste, the Warrior caste. Neroon came to idolise Branmer but developed a distinct hatred and distrust of both humans and the Religious Caste. After Branmer's death, Neroon accompanied his body on a tour of Minbari-occupied space (in defiance of Branmer's final wishes to have a simple cremation ceremony and scattering his ashes in space over Minbar), and was ready to start the war again when the body suddenly went missing (Legacies).
After the transformation of Delenn in 2259, he replaced her on the Grey Council, creating for the first time an imbalance of power between the castes.
He was not impressed by the revelation of the Grey Council's secret and was angry at the years their leaders had been concealing the truth about the end of the war from the Minbari people. He blamed, or appeared to blame, the religious caste for this at that time, referring somewhat later to "the usual fanaticism we've come to expect from the religious caste". It took Delenn's honesty and willingness for self-sacrifice for the good of their people, and the revelation of the corruption rampant amongst his own caste's leadership, to make him change his mind (All Alone in the Night).
At the climax of the Minbari Civil war, Delenn challenged the leader of the warrior caste to stand in the Starfire wheel, a dangerous energy field and a symbol of leadership. The head of the warrior caste ultimately surrendered and left the circle, but Delenn stayed, intending for the death of a religious caste member to end the war. Moved by her bravery, Neroon took her place in the wheel. Declaring that in his heart, he was always a member of the religious caste, he died and ended the war (Moments of Transition).
Neroon was a complex character, a person of principle and courage who was deeply affected by his war service, a person of deep loyalties who was nonetheless eventually capable of seeing beyond these. Who came to realize that the greatest courage is to admit when one is wrong, and to do whatever is necessary to make up for it, no matter the personal cost. When Delenn then restored the Grey Council, she held the leadership position of the Council open, stating: 'This place is reserved in memory of Neroon, until the day it is taken by the one who is to come'.