You met an Elyos named Erebus in the Indratu Fortress who expected your arrival. He asked you to help him by killing the Drakan commanding the Draconutes and Nagarants. You infiltrated the Indratu Fortress with your allies, killed Drakan, and collected their tails as proof you completed the mission. Erebus was pleased, and told you that he might need to assign you the same mission later because the Indratu Legion reinforces its troops quickly.