The Rohirrim is the warriors of Rohan their villages torn apart by Grima-Worm-Tongue and, Isenguards orcs and uruk-hai they flee to Helms Deep their greatest stronghold only to battle to the death against 10,000 uruk-hai. They hold off the uruk-hai aided by elves of Rivendell and then by Gandalf with the banished Eamor and his Rohirrim.
The Rohirrim soon return to Eadoras the the great hall of Rohan. they drink and they laugh enjoying their victory at Helms Deep. only to find the beacons of Gondar lit.
They decide to answer and remuster the Rohirrim knowing full well few will return home.