A moratorium is in effect on adding information from Fire and Blood until December 20th.
Kingspyre Tower is the largest and tallest of the five towers of Harrenhal. The original name for the tower was lost when Harren the Black and his sons died during Aegon's Conquest. It received its new name when Aegon I Targaryen had his dragon, Balerion, burn Harren and his sons alive in the tower.
The tower is lopsided beneath the weight of slagged stone, the result of Balerion's dragonfire. There is an arching stone bridge that connects it to the Widow's Tower. The castellan's chambers are within this tower, and are as spacious as any lords.
Prince Daemon Targaryen led the assault on Harrenhal at the start of the Dance of the Dragons. The castellan of Harrenhal, the elderly Ser Simon Strong, was quick to strike his banners when the prince and Caraxes lighted atop Kingspyre Tower.