The War of Succession was a military conflict over control of the throne of the kingdom of Apicarta.
Following the assassination of Tristan Stirling, his twin sons, Aldous Stirling and Claudius Stirling, contested each others' right to the crown. Claudius gathered supporters and waged war against his brother for three years. Aldous was in a defensive position and had more followers, giving him an advantage.
Among Claudius' supporters was Lord Gavin Zosimus, the most wealthy man in the kingdom. During the Battle of Duat, Gavin sacrificed himself to save Claudius, but the battle became a turning point in the war, favoring Aldous. Zosimus' family was taken hostage by Aldous, who later married his daughter Laura.
Eventually, Claudius went into hiding, adopting the false identity of William Harding. His sister Helen, who had been acting as a spy for him, was captured by Aldous shortly after. She revealed the whereabouts of Claudius to Aldous, believing if she told him where he was, Aldous would let him live.
While Aldous was still searching for Claudius, a second pretender, Aldous' cousin Frances, appeared. Through the machinations of her father, Sebastian, she was crowned queen at the capital in Aldous' absence. Aldous returned with his brother in chains to find his cousin on the throne. However, Frances willingly gave up her seat of power and submitted to imprisonment, having faith that Aldous would be merciful if she did so.
Sebastian mounted an attack on the capital in an attempt to free his daughter, but failed. He was captured and Aldous, convinced his enemies were all too dangerous to be left alive, had them all executed. Claudius was killed first, then Sebastian, then Zachary Guildford (Frances' husband), and finally Frances.