Firstborn (Dragonlance Elven Nations, Vol 1)

Silvanos, the august founder of the united elven nation known as Silvanesti, Is dead and buried in a crystal tomb. The leadership of the clans and households has fallen to his son, Sithel, who is himself father of twin sons. The princes Sithas and Kith-Kanan represent emerging factions among the elves: Kith-Kanan is the leader of the Wildrunners, a group of elves that stirs tension by forging contacts and trade with the humans of Ergoth; Sithas closely allies himself with the court in the elven capital. The rivalry between kin climaxes with their father’s mysterious death.

When Kith-Kanan is vaguely implicated, Sithas the firstborn twin, is enthroned.