Aegir asked you to find Agnita's servant so you could free the Daeva of Fire from the Fire Temple. You had to face Chalice Guard Denlavis inside the Fire Temple, just as Bulagan and Piyama had foretold. After defeating Chalice Guard Denlavis, you were able to take hold of the goblet that Agnita had been banned into. So you brought the goblet to Piyama so that Agnita could be released.