Echo

"Leo: "That must be fun." Echo: "Fun."Leo: "Blue Elephants." Echo: "Blue Elephants." Leo: "Kiss me, you fool." Echo: "You fool." Leo: "Hey!" Echo: "Hey!" Hazel: "Leo, don't tease her.""

- Leo teasing Echo Echo was an Oread (a mountain nymph) who loved her own voice. However, for aiding Zeus in consorting with beautiful nymphs, Hera cursed her to only being able to repeat the words of others.

History
Echo was a young and beautiful nymph that would sometimes help Zeus when he came down from Olympus. While Zeus was off flirting and consorting with other nymphs, Echo would tell stories or songs to his wife Hera to distract her. Eventually, Hera discovered the trickery and cursed Echo to only ever be able to repeat the words of others.

Eventually, Echo saw a man named Narcissus hunting in the woods and followed him, hoping he would introduce himself so she could talk back to him. When Narcissus was out hunting stags, Echo stealthily followed the handsome youth through the woods longing to address him but unable to speak first. When Narcissus realized he was being followed he called out "Who's there?"

Being forced to repeat him, she called back the same question which only served to confuse Narcissus. Still unable to see her, he asked why she was running from him, to which she replied with the same question. Finally he says "Let us meet together." Echo repeated the words enthusiastically, running from the woods and wrapping his hands into her own. However, Narcissus ran away from her claiming "May I die before what’s mine is yours." Echo only repeated "what's mine is yours."

Later, Echo found Narcissus looking at his reflection in a pond. Narcissus, who had fallen in love with his own reflection as punishment for breaking the hearts of so many girls by Nemesis, would talk to his reflection and say how much he loved it. Echo, who would watch Narcissus would repeat everything Narcissus said to his reflection. He eventually died however when he drowned in the small lake.

Echo died when she refused the advances of the god Pan, who had fallen in love with her. As punishment, Pan caused a panic, causing the people in the area to kill Echo and scatter her all over the land. Gaea collected the pieces and made it so Echo could be heard all over the world.

The Mark of Athena
Echo appears when Hazel Levesque and Leo Valdez go looking for Celestial Bronze and lime on a small island. After Leo tries to figure out who the cursed boy Nemesis mentioned was, he hears a girl repeat what he said, but can't see her at first. However, he is able to eventually find her after his eye's adjusted; her appearance is camouflaged and he finds it difficult to focus on her features. The girl seems forced to repeat everything Leo and Hazel ask, leading them to the conclusion that she is Echo, from the myths. She is another soul that had escaped the Underworld using the Doors of Death. Leo at first teases her a bit, trying to get her to say funny things, but she quickly turns it around on him and Hazel pleads with him to stop. Echo is able to ask Hazel and Leo for help and leads them to the lake where Narcissus is. On the way, they keep losing her, as she mirrors any background she walked in front of, causing her to constantly appear camouflaged.

When they make it to the small pond, they find Narcissus sitting on the shore looking at himself in a Celestial Bronze shield, which Leo needs to fix the Argo II. The other nymphs become very aggressive towards Echo, saying she already had her chance with Narcissus and is not good enough for him. Echo only wants to make Narcissus stop looking at himself to prevent him from dying like he did during his first life, but the other nymphs want him to stay by the pond staring at himself because they also love to stare at him. Hazel and Leo need to get the bronze out of the pond anyway, and Echo hopes that this will help her save Narcissus.

In order to save Narcissus and get the bronze shield, Echo helps Leo in his plan to distract Narcissus and the nymphs long enough for Hazel to get the shield from the water, using her power over precious metals. Leo gets a makeover, and proceeds to return to the pond, making a big show of calling Narcissus weak. Echo repeats all of Leo's words, but because few could see her, some nymphs thought it was one of the nymphs in their group instead of Echo. That helps to confuse and distract them. After Narcissus becomes so annoyed that he turned away from the bronze, Hazel pulls the bronze sheet from the pond while everyone is distracted and runs with it. By the time Narcissus figures out the trick, Hazel is already running, but he quickly orders the nymphs to get the shield back. Echo unwillingly repeats his command. While Hazel and Leo wait at the shore of the lake for Arion to pick them up, both Hazel and Echo stand in front of Leo to protect the shield. This surprises Leo and he compliments Echo on her bravery. He also tries to get her to forget about Narcissus and come with them instead. However, when Arion arrives, Echo tells them to leave her behind, as she still hopes to one day save Narcissus. Before he leaves, Echo kisses Leo on the cheek and he can see her real face for just a moment. He thinks to himself that he will never forget what her face really looked like, which he realizes was actually quite pretty, but finds that the memory is slipping away only moments later.

Personality
Despite originally being punished for being a gossip and helping Zeus, Echo is very humble and gentle. She is deeply in love with Narcissus and hopes that she will be able to save him, despite the interests of the other nymphs. Despite Narcissus not caring for her at all, she is completely devoted to him and tries her best to help and protect him. When Leo aids her by stealing the shield that Narcissus was using as a mirror, Echo stood against a large number of other nymphs to aid in Leo's escape, showing that she isn't afraid to put her life in danger as long as it helps Narcissus. Despite Narcissus not caring at all for her, Leo is able to see just how good of a person she is.

Appearance
Echo is a young girl. She wears a Greek-style tunic which changes color depending on the surface she is standing in front of. Because of her curse, Echo appears almost invisible, as her body will mirror any background she is standing in front of. When she was standing in a field, her hair appeared wispy and looked like a mixture of brown, blonde, and gray to match with the dried grass around her. When Leo looked at her face, he mentioned that is was pretty, but not memorable and found himself having a hard time actually remembering what it looked like. However, when she kissed him later, he could see her face clearly and marveled at her blue eyes.

Abilities
Because of her curse, Echo can only say the last thing she hears others say, but can't say anything on her own. However, the curse also allows her to hide very easily as her body will blend into whatever she is standing on or in front of. She has some control over how much she repeats, and can control her tone of voice to effectively communicate.

Trivia

 * Echo is the only person (besides Hazel) to be revived using the Doors of Death yet does not work for Gaea in any way.