During the time when the War of the Ring began when the One Ring had awoke and was destined to return to Sauron, Thalisule was among the elves that refused to leave Middle-earth and prefer to fight against the enemies of Mordor. Unlike the War of the Last Alliance that happened at the final year of the Second Age, Thalisule accompanied Haldir of Lórien to the old fortress of Helm's Deep where they aided King Théoden and his small army in defending the fortress of Saruman's army of 10,000 Uruk-hai that were tasked by their leader to destroy the people of Rohan. To prevent such atrocity, Thalisule and his kin were stationed on top of the Deeping Wall. He was standing behind Legolas and Gimli, looking onwards at the arrival of Saruman's army. As the Uruk-hai prepared to lay siege, Thalisule l