<Ul> <Li> Briares--Briares is a Hekatonkheires . Briares was imprisoned on Alcatraz Island by Kampê in the fourth book . It is mentioned that his brothers Cottus and Gyges have faded because people have forgotten about them . When Tyson finds that Briares (his hero) is too afraid to escape, he is heartbroken . At the end, Briares returns to help defeat Luke and the Titans . In The Last Olympian, Percy sees Briares helping Poseidon defeat the forces of Oceanus . </Li> </Ul> <Li> Briares--Briares is a Hekatonkheires . Briares was imprisoned on Alcatraz Island by Kampê in the fourth book . It is mentioned that his brothers Cottus and Gyges have faded because people have forgotten about them . When Tyson finds that Briares (his hero) is too afraid to escape, he is heartbroken . At the end, Briares returns to help defeat Luke and the Titans . In The Last Olympian, Percy sees Briares helping Poseidon defeat the forces of Oceanus . </Li> <Li> Hyperborean--The Hyperboreans are a race of 30 ft . Snow Giants with blue skin ice - gray hair that come from Hyperborea . When wounded, the Hyperborean will bleed blue blood . They can freeze object and people using their frosty breath . When defeated, the Hyperborean freeze into ice . In The Last Olympian, the Hyperboreans are on the side of the Titans . In The Son of Neptune, a group of peaceful Hyperboreans were seen in Anchorage, Alaska . <Ul> <Li> Morrain--A Hyperborean who appeared in The Last Olympian . He was a part of a truce meeting . He wasn't seen taking part in the Battle of Manhattan and his current fate is unknown . </Li> </Ul> </Li> <Ul> <Li> Morrain--A Hyperborean who appeared in The Last Olympian . He was a part of a truce meeting . He wasn't seen taking part in the Battle of Manhattan and his current fate is unknown . </Li> </Ul>

Who are the main characters of percy jackson