Battle of Mount Othrys

The Battle of Mount Othrys was the final engagement in the Roman demigod side of the Second Titan War, at the same time as the Battle of Manhattan. The Roman demigods, commanded by Jason Grace son of Jupiter, assailed the Titan fortress of Mount Othrys, confronting an army of Scythian dracanae and the Titan Krios.

The Last Olympian
Camp Jupiter's army, led by Jason Grace, battled the Titans that were staying at the base. Jason toppled down Kronos' black throne, and destroyed the Titan Krios. Mount Othrys soon crumbled to ruins, as part of the defeat of Kronos.

The Lost Hero
While discussing how Mount Othrys collapsed as a result of Kronos' defeat at the end of the Battle of Manhattan. However, Jason began to remember the battle and at one point proclaimed "I toppled the black throne of Kronos and destroyed the Titan Krios with my own hands!" While Titans are immortal and thus cannot be completely destroyed, it is presumed that Krios' physical body was destroyed and his essence returned to Tartarus. Jason had also remembered flashes of the battle: a giant in starry armor and a helm mounted with a ram's horns. He remembered an army of Roman demigods scaling Mount Tam, fighting through hordes of snake monsters. When he reached the top, he defeated Krios and destroyed the throne, unknowingly aiding the Greek demigods that were protecting Olympus in Manhattan.