You were on Arlongs crew but left to join the Straw Hats.While you were on his crew you and Arlong ended up having a daughter.You tried to take her with you but he kept her.Since you had found the map to the Grand Line Arlong said he would trade you your daughter for the map.You agreed to meet him in Arlong Park.You walk in to see Arlong and all the other fish men with one holding your baby.You walk over to Arlong with the map to the Grand Line.