d0f74f4b_ions_and_Hints___Team_Ico_Wiki__Dormin_s_description
[Colossus] Valus [Hints offered during battle] Hold up thy sword to reflect the light onto the colossus. Its vitals shall be revealed... Thou must climb the colossus to reach its vitals... [Dormin's description] 
Raise thy sword by the light... and head to the place where the sword's light gathers... There, thou shalt find the colossi thou art to defeat.
Dormin's Colossus Descriptions and Hints - Team Ico Wiki
Dormin's description