Mayura

"It’s true. Things aren't going as planned, for me either. I should have never taken this job. It’s too much sometimes. As I watched Adrien growing up, my affection for him has grown too. As I've watched Emilie falling deeper into an endless sleep, my sadness for her has deepened too. And little by little, my admiration for Gabriel—a man who'd do anything for his family—has turned into something more. I never thought I'd have feelings like this. I would do anything for Gabriel Agreste, no matter the cost..."

- Nathalie reflecting on her relationships and motives.

Nathalie Sancoeur, later known as Mayura and Catalyst while using the Peacock Miraculous and in her akumatized form respectively, is the secondary antagonist of Miraculous: Tales of Ladybug and Cat Noir.

She is the assistant of Gabriel Agreste/Hawk Moth, who later starts to use the Peacock Miraculous to help him in his quest to steal the Miraculouses of Ladybug and Cat Noir. She is also the creator and master of the Sentimonsters; creatures made from the emotions of those she targets.

She is voiced by Nathalie Homs in the original French version, and by Sabrina Weisz in the English dubbed version.

Appearance
As Nathalie, she stands at an average adult height, and her eyes are a dull blue. Her hair is black and pulled back into a bun, and the hair on the right side of her head is dyed red. On her face Nathalie has glasses with black and red striped frames and on her eyes she has periwinkle eye shadow. She wears a red turtleneck sweater, a black dress jacket, black pants, and black high heel shoes. She also has round creamy white earrings.

As Mayura, her eyes have pink irises and sclerae that are pink which fade into dark indigo, and there is black liner around her eyes, resembling glasses. Her skin is a light indigo and her hair is dark blue, and part of it curls up underneath her left eye. She wears a peacock feather-like cocktail hat, being blue and tear-shaped with a light pink mark in the center and a light blue, translucent veil over her right eye. She wears a blue dress with a fuzzy black collar and sleeves that end in a point on the back of her hand. The dress appears to have a set hexagonal texture. The bottom of the dress has a front slit skirt, and the end of the skirt has rounded points with dark blue, light pink-centered spots, resembling a peacock's tail feathers. The rounded points are edged with translucent, light blue material. Underneath the dress, she has translucent indigo tights that are opaque from the knees down, making the opaque section resemble high heeled boots. She holds a blue hand fan, which is similar in design to the end of her skirt, and a peacock feather-like object in her other hand.

As Catalyst, she has periwinkle skin. Over her head, while leaving her mouth exposed, she wears a black helmet with a red visor with black edges and a red spike pointing towards the back of her head. Catalyst also wears a black dress suit with stiff shoulders, including a dark red front and swan neck collar that features a red downward arrow-shaped section in the center. The sleeves cover her entire arms, with the tips of her fingers fading into red. Also, Catalyst has pocket-like ridges on each side of her hips, and her pant legs come down to her feet, having red high-heels, soles, and tips.

Personality
Nathalie possesses a rather cold and distant demeanor, very rarely showing her emotions around others. She is consistently serious, organized and diligent in performing her duties as Gabriel's assistant, yet is otherwise cordial and professional when it comes to dealing with others, such as reasoning with either Adrien or Gabriel when they act inconsiderate or emotionally (typically in relation to one another) or when assisting Ladybug with protecting Gabriel in "Simon Says". She can also be extremely fearful of disappointing Gabriel, panicking after realizing she forgot to get Gabriel a birthday gift for Adrien in "The Bubbler", and quickly deciding to disguise Marinette's scarf as a gift from the former instead. She seems to care greatly about Adrien in general, and does her best to provide for the Agreste family.

As shown in Season 2, Nathalie is not only dedicated to but incredibly loyal to Gabriel, as she is not only aware of his activities as Hawk Moth but openly supports him in his efforts to steal Ladybug and Cat Noir's Miraculouses. As such, she seems to be slightly sociopathic, having almost no concern for the consequences of Hawk Moth's actions, not even when they affect her directly. Like Gabriel, she also has a hatred of Ladybug and Cat Noir (though to not nearly to the same level) and wants to see them defeated, fully accepting Gabriel's plan to akumatize her and recreate most of his akumatized villains in "Catalyst (Heroes' Day - Part 1)", taking sadistic joy in fooling the heroes into thinking they can win all the while. She is furthermore willing to take any risks if it means protecting him, leading to her deciding to use the damaged Peacock Miraculous to help him escape capture.

Gabriel Agreste/Hawk Moth
Nathalie works as Gabriel's assistant and is incredibly loyal to him, supporting his efforts in trying to obtain Ladybug and Cat Noir's Miraculouses despite them being morally wrong. She admits to have feelings for him and would do anything for him no matter the cost. She even allows him to akumatize her and later risks herself by using the damaged Peacock Miraculous to aid him when he is cornered by the French Miraculous superhero team.

Adrien Agreste/Cat Noir
Nathalie is in charge of watching over Adrien and organizing his schedule. Though she treats him in a formal manner and is not very warm or close to him, she does care greatly about him and looks out for his interest and well being; requesting Gabriel to allow him to attend public school after seeing how much he wanted to go, wishes him a Merry Christmas on Christmas Day, and showing some sympathy towards him when he is let down by his father, even suggesting to Gabriel that he spend more time with his son occasionally.

With Cat Noir, however, Nathalie is more antagonistic, being willing to destroy him and take his Miraculous to suit Gabriel's goals. In "Catalyst (Heroes' Day - Part 1)", she openly states that she will go to any length to get rid of him and Ladybug for standing in Gabriel's way, and has no problem with fighting him directly as Mayura in "Miraculer", almost defeating him before Ladybug's intervention.

Marinette Dupain-Cheng/Ladybug
Nathalie has seldom encountered Marinette personally, only seeing her in person during the derby hat competition in "Mr. Pigeon" and briefly interacting with her in "Style Queen (Queen's Battle - Part 1)". However, on Adrien's birthday in "The Bubbler", she treats Marinette formally when on a speaker and disregards her by claiming to Adrien that Marinette's gift was from Gabriel.

Like with Cat Noir, Nathalie, though shown to be willing to work with her in "Simon Says" (if only for the protection of the Agreste family), holds great disdain for Ladybug and wants to take her Miraculous; possibly even more so than with her other allies as she is typically the one who disrupts Hawk Moth's plans the most.

Chloé Bourgeois/Queen Bee
Like most Parisian citizens, Nathalie is aware that Chloé is Queen Bee. As Mayura, she tries to convince Chloé to join her and Hawk Moth, promising her that if she does, she can be Queen Bee whenever she likes, though Chloé refuses.

Pre-series / Season 1
Though Mayura herself was absent during this time, her civilian identity, Nathalie, was usually seen at the Agreste mansion alongside her boss Gabriel Agreste and Adrien's bodyguard.

Season 2
In the episode "The Collector", it is revealed that Nathalie is aware that Gabriel Agreste is Hawk Moth when she asks the latter why he went after the book which Adrien had lost earlier if he already had another one, to which Gabriel answers that he had to hide his secret identity from Ladybug and Cat Noir.

In the episode “Style Queen”, Nathalie goes along with Gabriel’s plan to akumatize Audrey Bourgeois by telling her that she has a second row seat at his fashion show as opposed to a front row seat. After Style Queen’s defeat, Nathalie comments on the big risk Gabriel took involving his son getting turned into a glitter statue.

In the episode “Queen Wasp”, when Gabriel decides to quit being Hawk Moth and sadly sulks over his wife, Nathalie hugs him and then accompanies him to his fashion show. Later on, when Gabriel changes his mind about quitting being Hawk Moth, Nathalie confronts him about it. Gabriel tells her that he can’t give up, as he misses his wife too much. Though Nathalie understands, she can’t help but feel sad for him.

In the episode "Catalyst (Heroes' Day - Part 1)", Nathalie helps Hawk Moth to get Ladybug and Cat Noir's Miraculouses by letting him akumatize her into Catalyst, a power-enhancing supervillain. Then Nathalie, as Catalyst, turns Hawk Moth into Scarlet Moth, boosting his powers so that he can create as many akumas as he wants.

Mayura makes her debut in the final episode with the same name "Mayura (Heroes' Day - Part 2)". After seeing that Ladybug and Cat Noir defeated Scarlet Moth and the scarlet akumatized villains, Catalyst becomes enraged. She takes the Peacock Miraculous and transforms herself into Mayura in order to help Hawk Moth. She then helps him escape the heroes. Later, a weak Nathalie is shown with the Peacock Miraculous alongside Gabriel Agreste.

Season 3
In the episode “Stormy Weather 2”, Nathalie reveals that she regrets taking her job, as it has become too much for her. She also admits to feeling affection for Adrien, sadness for Emilie, and admiration for Gabriel. She claims that she would do anything for the latter, no matter the cost.

In the episode "Miraculer", as the rest of the French Miraculous superhero team fights Hawk Moth's newest villain, Mayura waits besides Chloé Bourgeois' house for Ladybug to give her the Bee Miraculous. When this doesn't happen, Nathalie and Gabriel take note of how reluctant Ladybug seems in giving Chloé the Bee Miraculous and decide to use Lila Rossi's psychological talents in order to make Chloé lose faith in Ladybug and become vulnerable for akumatization. As part of Hawk Moth's plan, Mayura sends a feather to a crying baby August, creating a giant lollipop sentimonster. While the plan to akumatize Chloé ultimately fails, Hawk Moth is able to akumatize Chloé's best friend Sabrina into Miraculer, a power-stealing supervillain. Due to the villain stealing both Ladybug's and Cat Noir's powers, Ladybug decides that she needs everyone -- including Chloé. However, before Cat Noir can hand Chloé the Bee Miraculous, Mayura snatches it and tells Chloé that if she joins them, all her dreams will come true. During the battle between Miraculer and the French Miraculous superhero team, Hawk Moth tells Mayura to come back to him as she has the Bee Miraculous. However, when Mayura begins to take off, Cat Noir knocks the Bee Miraculous out of her hands and Ladybug snatches it. As Mayura runs away, Ladybug gives the Bee Miraculous to Chloé and tells her to follow Mayura, to which Chloé agrees and transforms into Queen Bee. She engages Mayura in combat, though Mayura manages to pin her down and tries to convince her to join her team by promising that she can be Queen Bee whenever she likes. However, Queen Bee refuses and escapes Mayura's grasp. She nearly succeeds in taking the Peacock Miraculous off her, but Mayura manages to escape before she can. After Miraculer's defeat, Mayura apologizes to Hawk Moth for failing, but Hawk Moth tells her that it's okay as he is confident that Queen Bee will change her mind.

In the episode “Timetagger”, when Gabriel expresses grief over the fact that him not being Hawk Moth in the future may mean that he’s failed his mission, Nathalie reminds him that it could also mean that he succeeded as the future is not set in stone.

As Catalyst

 * Power Enhancement: Catalyst's main ability is to boost the powers of Hawk Moth, allowing him to akumatize multiple people at once.

As Mayura

 * Amoktization: Reminiscent of Hawk Moth's akumatization, Mayura has the ability to empower one of the amoks from her hand fan and send it out to infect an object associated with someone. Once the object has been infected, Mayura can create a Sentimonster from said person's strong emotions, which protects them and can be dissolved by Mayura at the snap of her fingers.
 * Telepathy: Similar to how Hawk Moth can communicate with his akumatized victims, Mayura can also communicate with her victims telepathically.

Season 2

 * Giant Purple Butterfly: Created out of Hawk Moth's despair at being cornered by the French Miraculous Superhero Team. It can fly and create powerful gusts of wind by flapping its wings.

Season 3

 * Lollipop Monster: Created out of the infant August's frustration at being denied a lollipop by his mother. It is massive in size and has proportionate strength.

Quotes
"They've been keeping you from achieving your dream for way too long. I will go to any length to end the reign of Ladybug and Cat Noir!"

- Nathalie to Hawk Moth.

"Hawk Moth, I give you the power to release as many akumas as you desire. From now on, you are the all-mighty Scarlet Moth."

- Catalyst boosting Hawk Moth's powers. "Nothing's more delightful than leading them to believe that they actually have a chance of winning when their future has already been decided!"

- Catalyst to Hawk Moth. "Hawk Moth...I am Mayura. You're up against the world, plagued by your deepest, darkest despair. Let me help you! (Hawk Moth: No! Don't do that!) Let your despair be embodied in a powerful protection!"

- Mayura introducing herself to and using her powers on Hawk Moth.

Trivia

 * Mayura is the Sanskrit word for peacock, which is one of the sacred birds in Hindu mythology. It is also a contemporary Hindu name used in many parts of India.
 * While the villain is female, "mayura" is specifically the term for males, while "mayuri" is the term for females.
 * Unlike the other akumatized villains, Nathalie isn't akumatized due to negative emotions, but rather a real desire to help Hawk Moth.
 * Also, Catalyst is so far the only akumatized villain not to be defeated by the French Miraculous superhero team and the only one they are not aware of.
 * Mayura is so far the second known Miraculous holder to use their power for evil after Hawk Moth
 * Her old name was Le Paon.