sentences:  It is often claimed that, until the 18th century, the Iara legend did not pertain to the image of a seducing, docile river mermaid.Instead, it was originally about an aggressive and monstrous river merman known as Ipupiara ("freshwater monster"), which would readily devour fishers.Iaras are immortal (like the nymphs of Greek mythology), but many of her lovers do age or die.