Aranaethanah (Arantha) Aetherplith is the older brother of Aarlam Aetherplith and the eldest son of Ophelia Aetherplith. As one of the last remaining rangers in the Southern-Mistlands pass, Arantha was able to track the small band of Boar-knights from Ankoria to Aldendan. Because of his skills and efficient speed, Arantha was able to anticipate the Boar Knight's destination and arrived in Aldendan before them. Originally, the Elves were reluctant to assist the Morcians, however, Arantha's co-operation with Knight and Matteu persuaded them to join the alliance of Morcia in 1335.
All that is known of Arantha's father is that, he was King of the Elflands and patriach of the Aetherplith family, until his death at the battle of Mistland's tower. Arantha was in his early thirties at the time of his father's death; still in his Elven childhood and too young to fight in the war. Arantha swore to avenge his father by killing Lord Vladek but was unable to do this while his soul was preserved in the Blacksmith's Crystal. Arantha's choice to live the solitary life, as a ranger in the Southern-Mistlands pass may have been influenced by the possibility of Vladek's escape; if and when the Crystal failed/was activated/was destroyed, Arantha would have first attempt to kill him, thus avenging his father.