Pierrot

Pierrot is a Level 2 Akuma that originally appeared as a Level 1 in Mater, where it attmpted to steal the doll, Lala's, Innocence heart.

Appearance
Pierrot's original appearance was that of a basic Level 1, though when it was first seen its Level 1 body had swelled to show it was on the verge of evolution. Once it had evolved, it took a more humanoid form, specifically with the appearance of a jester, complete with a belled hat and striped outfit. Its proportions, though, were skewed; it had elogated, skeletal arms, large hands and wide hips. It also had a pair of black wings.

Personality
As a Level 1 Akuma, Pierrot was a mindless killing machine. Upon evolving to Level 2, it gained intelligence and a distinct personality, which like most Akuma, was bloodthirsty and sadistic, taking pleasure in hunting down those around it and killing/torturing humans slowly. When angered, though, it would quickly get consumed in a berserker rage in which the need to kill those in its way took precedence.

Ghost of Mater arc
Originally appearing as a Level 1 on the verge of evolution, Pierrot manages to shoot a Blood Bullet through a Finder's talisman barrier and evolve into a Level 2.

After it evolves, Pierrot beginst to chase Guzol and Lala, who are being protected by the Finders, through the Mater underground. When it corners them outside and the Finders set up a protective talisman barrier around them, Pierrot orders the remaining Level 1s to fire upon the barrier in hopes of breaking it, Pierrot keeping a Finder hostage and torturing him. Allen Walker and Yu Kanda, accompanied by the Finder Toma, then arrive, Allen engaging Pierrot in combat while Kanda retrieves Lala and Guzol.

When Pierrot realizes that Allen is an Exorcist, it becomes ecstatic, only to become enraged immediately after when it sees Kanda taking off with Lala and Guzol and is forced to choose between fighting Allen and hunting the Innocence down. As it fights Allen in its rage, it copies his appearance and attacks him with a 'copy' of his own Cross on its arm.

When Allen is stunned by Pierrot's appearance and ability to copy his cross, the Akuma taunts him, saying that Allen underestimated it and that, because it evolved, it gained new abilities. It then alters its version of Allen's body and turns its copy of Allen's Cross into a trident, attacking Allen and damaging his Anti-Akuma Weapon. Allen then falls through the floor, leaving Pierrot without an opponent. Pierrot then turns its attention to Allen's golem, Timcanpy, and begins assaulting him.

When the Finder Toma reports this to Kanda, Kanda tells Toma to retrieve Timcanpy and come to him. Initially, it seems Toma has done this, but when they run into a clear copy of Allen and Kanda attempts to attack the copy, thinking it is Pierrot, Allen comes out of a nearby chamber in the wall and defends the copy of himself, revealing that, using his eye, he can tell that the 'Toma' Kanda had been interacting with was really Pierrot. Exposed, Pierrot, still partially wearing Toma's visage, attacks Kanda, wounding him severely.

Greviously wounded, Kanda appears to die standing up, something that amuses Pierrot greatly. An enraged Allen attacks Pierrot while he is distracted and tears him in half, then takes Kanda and Toma and flees with them.

Once he has recovered, Pierrot tracks Allen and the others down and, seeing Lala and Guzol are with them, attacks the human and the doll, running them both through and tearing the Innocence from Lala's body. This action, which has stolen the life and personality that Lala has developed over the years, enrages Allen, causing his Anti-Akuma Weapon to warp into a cannon, which Allen attacks Pierrot with.

To defend himself, Pierrot uses his ability to take the form of the sand of the room they are in, entrapping Allen within his sand body and stabbing him with his copy of Allen's Cross. His weapon, though, breaks against Allen's Anti-Akuma Weapon, and Allen then turns his Cross into a sword-like beam he uses to peel Pierrot's sand skin from his body.

As Allen presses forward, though, his body starts to give out, Pierrot takes the opportunity to press forward, only for Kanda to intervene and protect Allen. Together, Allen and Kanda combine their strength and attack Pierrot, destroying him.

Powers and Abilities
Inherent Akuma Abilities: In its Level 1 form, Pierrot had all of the abilities inherent to a Level 1, including Blood Bullets.

Paper Mirror: Once it had evolved into a Level 2, Pierrot gained the ability to physicially mimic other living beings and even inanimate objects like sand. He called this ability a "Paper Mirror", as he was also able to take off his skin and superimpose it onto others to disguise them however he wanted. Pierrot's ability, however, had shortcomings: all of his copies were exact mirror images, meaning that they were not symmetricial and that charactersitics that appeared on one side of an individual appeared on the opposite side on him and those he imposed them on, and despite being able to copy Allen's Cross, he could not copy its strength.

Trivia

 * In the anime, it is said that Pierrot is a male Akuma with a female soul.
 * This Akuma was originally unnamed in the manga version. "Pierrot" was the name given to the character in the anime version.