Santa Claus

Santa Claus (サンタクロース) is a mysterious woman who has a contract with the Doll Devil allowing her to control several different bodies, one of which poses as a Devil Hunter from Germany. However said woman, also known as Master, could also possibly be one of the bodies herself, and not the original, as Santa has stated that anyone can become the assassin known as Santa Claus with a mere touch by the dolls she controlled all around the world.

Santa Claus is the primary antagonist of the International Assassins arc.

Appearance
Santa Claus is presumably a dark-haired woman with a mole under her eye. She wears a dark skirt and a light sweater.

After she ate a piece of Darkness Devil's flesh, she gained several doll arms and appendages and her legs were made of doll heads. During night, she transformed and became larger and more devilish. She also grew horns and sharp teeth.

Personality
Santa Claus is a tactical and strategical being. She hid herself within the Soviet Union, while using a perfect doll to bargain and negotiate. When introduced, Santa Claus appear to be a lecherous being who asked for several children of either gender as their reward for bringing in the Chainsaw Devil from Japan, apparently for use in contracts and for pleasure (although this is presumably to instill strong emotions into them and groomed them to be the next perfect doll). It is later revealed that three of the children are meant to be used for contract with Hell Devil along with the old man perfect doll.

She has no issues with forcibly recruiting large numbers of civilians to work for her by transforming them into puppets. She has shown no regard for those who seem to care for her. For example, when her ally Tolka had subdued Denji, Santa Claus turned him into a puppet to communicate with the Darkness Devil and complete the contract.

During battle, Santa Claus displayed a more ruthless tactic by transmitting her pain across puppets all over the world. In order to eliminate Quanxi, Santa brought back the personalities of some puppets to dishearten and kill Denji.

History
At some point of time, Santa Claus made a contract with the Doll Devil which allowed her to create dolls and perfect dolls, which then spread throughout the world. One of the perfect dolls of Santa Claus is a short, mostly bald elderly man with a thin mustache and beard, which became known as the Santa Claus of Germany (ドイツのサンタクロース, Doitsu no Santa Kurōsu). However, another body of Santa Claus remained residing in the Soviet Union, who is presumably Santa’s true body. She is there to train Tolka to become another perfect doll. She is referred to as Master (師匠, Shishō, lit. "Teacher") by Tolka.

International Assassins arc
She is hunting the woods with Tolka when they come across a fox which he shoots with an arrow. He questions the point of the hunt they're on while his master repeatedly asks him whether he thinks he has taken a life or not. They return to their cottage and cook the fox. She reveals that their next job is not a job to hunt a devil but to hunt and kill a sixteen-year old boy, much like the fox they have just hunted and killed. Tolka swears to her that he can kill. He makes a promise to her that since she has just half a year left to live that he wants her to live her remaining days in a peaceful retirement.

Makima and Kishibe discuss the potential threats that may be coming from overseas, with Santa Claus of Germany being among them. Makima states that she heard a rumor that "he" died of old age and Kishibe acknowledges that they should pray that is the case.

In Germany, a military man sat down at the same bench as one of the perfect dolls of Santa Claus who was reading a newspaper. He told Santa Claus that Christmas has come early, and that they want "him" to bring in the Chainsaw Devil from Japan. When asked for "his" desire for a reward "he" stated that "he" wanted to adopt four good-looking children for use in contracts and for pleasure.

Later, both herself and her perfect doll travel to Japan separately. Old doll came from Germany while she and Tolka come from the Soviet Union.

In Japan, she discretely stabs Denji three times with a nail and drops it in front of Tolka, who is sitting at a nearby table. She explains the details of their contract with the Curse Devil and entrusts the fourth and final stab to Tolka. Meanwhile, the old doll uses her contracted abilities to convert a crowd of people on a street into dolls.

Old doll hides within a coffee shop nearby to a department store that Denji and his bodyguards are visiting. "He" orders their dolls to attack once Denji enters the store. "He" continues to send in an entire army of puppets after Denji in preparation for delivering a present.

After Tolka kills Denji, Santa Claus comes to congratulate Tolka and tells him that he is now part of the family. She then turns Tolka into a perfect doll by touching him. At the same time, Santa Claus sacrifices her old doll and three of "his" beloved children as to use her contract with Hell Devil to transport the Devil Hunters along with Tolka to Hell. During this, the main body sits on a doll and watches as the hunters are transported to Hell. Tolka, one of her perfect dolls, states to the Darkness Devil that "he" has brought the Chainsaw's heart for the power to kill Makima. Darkness Devil has accepted this contract and grant her main body with the power of darkness, transforming into a monstrous being and after a short exchange of blows with Denji while marveling at her new regeneration ability, she have her now enhanced dolls went to attack Denji. A little later, a now transformed Quanxi attack Santa, but to no avail as Santa discovered that not only has her regenerative ability been enhanced but she could also split her sense of pain to her dolls. She then made all the dolls that was attacking Denji to regain their human consciousness.

Quanxi later attempts to help Denji fight against the Sapient Dolls who Quanxi claimed to be imitations of their human self before being seemingly stopped by Santa Claus as the latter attempts to attack Quanxi to no avail as Quanxi evaded the attack. However, as the nighttime hits, she becomes a lot more powerful with her body become increasingly nightmarish while brutally knocking Denji. When attacked by Quanxi, Santa Claus turns Quanxi's two precious girlfriend into a doll to be sic against her while Quanxi was impaled. Fortunately, Denji comes with a brilliant idea to uses gasoline and burns himself in order to defeat Santa Claus which immolates her and weaken her power which backfired a bit as Denji destroys Santa Claus's body by slamming a car towards her, later her conciseness is traped inside of Cosmo's Infinite World of Halloween where she is forced to learn all knowledge, making “Halloween” the only thing she can ever think of and say as her main body burn to ashes and all her dolls goes haywire.

Abilities
Makima and Kishibe hold “him” in high regard as the most dangerous threat towards Denji amongst the world's assassins and devil hunters as they say it will all be over if “he” uses “his” devils against them.

Devil Contracts
Doll Devil Contract: Santa Claus had a contract with the Doll Devil for an unknown price. Curse Devil Contract: Santa Claus was contracted with the Curse Devil. Hell Devil Contract: Santa Claus was contracted with the Hell Devil. Darkness Devil Contract: In exchange for bringing Denji to Hell, the Darkness Devil gave Santa Claus a small piece of its flesh, which she ate, which gave her a boost in several abilities such as:
 * Doll Creation: Santa Claus can create dolls out of people to obey his will. The effect is caused by touch and spreads contagiously as each doll touches another person, allowing them to create an army of dolls out of a crowd. The dolls can also transform one of their arms into blades including themselves. However Santa Claus must remain in the nearby area in order to maintain control of their army of dolls, and the conversion process has no effect on fiends nor hybrids. She could also made the doll regain their human consciousness, although it’s unclear if she always has this ability or has gained it after eating the Darkness Devil’s flesh.
 * Perfect Doll Creation: By instilling emotions that only humans can have into a puppet, such as respect, worship, admiration, and guilt, Santa Claus can turn people into perfect dolls, become a part of Santa Claus and are able to make devil contracts in Santa's place. Known perfect dolls include: Santa Claus in Germany, Tolka and possibly Master. Perfect dolls that is not currently directly controlled by Santa’s consciousness seem to be possessed by the Doll Devil itself as Tolka have referred to himself as the Doll Devil when talking to the Darkness Devil.
 * Mind Transfer: Santa Claus states that she can transfer her consciousness to any one of the dolls she has made across the world, effectively making her immortal as long as one of her dolls is still operating; this is expanded upon once she is initially trapped in Cosmo’s library, Santa had stated that flooding information into her mind would carry into every doll as her dolls share her consciousness to some capacity. However it isn’t clear if she has this ability prior to obtaining the Darkness Devil’s flesh or after, resulting in the ambiguity of wether or not Master is Santa’s original body.
 * Curse: In exchange for the loss of sensations on several of their fingers, Santa Claus can use the Curse Devil's power. The contract requires the nail to be stabbed 4 times into the intended victim, after which the Curse Devil will appear and kill the target. It is not required that the stabbing must be occurring at same time or by same person as it is shown that Santa Claus left the final stab to Tolka.
 * Transportation: Santa Claus can transport any living beings to Hell by naming the place they are currently in. However not only must they sacrifice three of their children, but they also need to sacrifice one of their own bodies as well. Later, Makima used this contract via one of their perfect dolls to return any living beings back to human world.
 * Enhanced Doll Devil Power: Santa is freely able to distribute her senses and pain to all of her dolls. She is also able to turn fiends and maybe even hybrids into doll when she previously couldn’t, although the latter is only speculated to be possible by Santa herself. The dolls she made have also been enhanced, as they are able to keep functioning despite being fatality wounded by human standards when they previously couldn’t.
 * Enhanced Strength: Santa was strong enough to hit Denji through several floors and walls. Her strength is augmented during nights.
 * Enhanced Speed: Santa was fast enough to jump from the ground to the top of a multi-storey building in a few seconds, she were also able to catch several arrows that were as fast as bullets. Her speed is augmented during nights.
 * Regeneration: Santa was able to heal her wounds by being in darkness, recovering from fatal injuries in an instant. This ability is augmented during nights.
 * Transformation: Santa became much taller, grew many more arms, and had many other changes to her body that resembled dolls. She grows even more devilish during nights.