Hector was charged to guard the Fountain of Youth by Juan Ponce de León 400 years ago, he was kept alive and young by its mystical water. Unfortunately, Hex was able to force him to reveal its location. He had led a lonely existence because if he became attached to anyone they would eventually grow old and die while he would continue to live, and warned a then-10 year-old Max Tennyson (rejuvenated by the Fountain of Youth) not to long for his kind of life. When the fountain was destroyed by Ben as Heatblast, Hector revealed that the effects of its water would gradually reverse themselves after a while. Thus, he would continue to age until his death.
His role is similar to the Grail Knight in Indiana Jones and the Last Crusade as he guards an eternal-life-giving object and stays alive by consuming the object The Fountain of Youth in Hector's case and in the Knight's case the Holy Grail.