Lala

Lala is the name of a puppet that lived for 500 years thanks to a shard of Innocence. She was the main plot in the Ghost of Mater arc, along with the character Guzol.

Appearance
She is a doll with the appearance of a young girl. She has blond hair and blue eyes (her left eye was broken and had to be covered with bandages) and a metal head-piece with two "horns" sticking out of it. She wears tattered clothes and a pointed hat when she was first introduced. During her flashbacks, she has long messy hair and her left eye was not covered in bandages.

Ghost of Mater arc
She is first discovered by one of the Finders in Mater. Because the Finders knew the Innocence was somehow linked to Lala and Guzol, they stayed with them and protected them from Akuma attacks, waiting for the arrival of the Exorcists. After Allen Walker, Yu Kanda and the Finder Toma arrive, she and Guzol are taken by Kanda to safety.

After relocating Guzol and Lala to the catacombs of the city, Kanda tells prepares to take the Innocence, with Guzol stepping up and saying that he is the doll. Lala puts herself between Kanda and Guzol, reasoning that Kanda cannot take the Innocence from Guzol yet because Guzol is the only one who knows the underground pathways. While Kanda was distracted by Toma bringing him the broken remains of Timcampy (who he uses to analyze the Akuma's abilities), Lala and Guzol flee further into the catacombs.

It is then revealed that Lala is the doll, not Guzol, and that they both lied so she could be with Guzol for as long as she could, both of them knowing it would not be much longer. She then sings a lullaby to Guzol, which Allen overhears when he runs across them trying to find a safe place to hide Kanda and Toma. When Allen walks in, revealing he knows Lala's true nature, she immediately attacks him, throwing the pillars that are scattered around the room at him.

After a short battle which ends in Allen destroying the pillars so she does not have anymore ammo, she tells Allen the story of the city and the dolls, revealing that after the people left Mater, she was left to wander the city alone. Wanting only to do what she was made for and sing for humans, she would ask each child that was abandoned in the ghost town if they wanted her to sing for them. When the children reacted violently, she killed them, ending the lives of five children in this fashion. When the sixth, Guzol, asked her to sing for him, she did not leave his side for eighty years.

She then reveals that Guzol is dying, and says she does not care what happens to her after he passes so long as Allen will let her stay with Guzol until his end. Kanda denies her request and tells Allen to take the Innocence from her before the Akuma returns. Allen refuses, and after saying he will take it, himself, after Guzol dies, Lala and Guzol are impaled by the Akuma.

The Akuma takes Lala's heart, the Innocence, and she is reverted to a regular, broken doll. Even after Kanda and Allen battle and defeat the Akuma, though, returning the Innocence to Lala, the spirit of Lala does not return, the doll, instead, being an ordinary doll who has none of Lala's personality and memories. The broken doll asks Guzol if he wants to request a song, Guzol tells Lala he loves her and dies. Assuming he has simply gone to sleep, Lala sings a lullaby.

Three days after she starts singing, Lala finally breaks down. When Allen goes to her side, Lala's spirit returns for a brief moment to thank him for allowing her to keep her promise. She then collapses, passing on, herself. This affirms Allen's desire to become "a destroyer who can save".

Trivia

 * The lullaby that she sang is called "Lacrimosa" or "Lala's Lullaby" in the soundtracks.
 * In the anime, she was later seen in Allen's flashback.