Akumatized villains

Transformation
Whenever a person has strong negative emotions, such as anger, frustration, jealousy, disappointment, humiliation or sadness, Hawk Moth senses it from his lair and charges a butterfly with dark power to form an akuma. The akuma then flies away from Hawk Moth's lair to where the person is, and possesses an important object that belongs to the person.

Immediately, Hawk Moth telepathically links up to the person in order to communicate, using a butterfly-shaped light mask that goes around his and victim's eyes. Also, in that moment, the area around the person's eyes darkens into a dark rust color. He then gives them a new name for their supervillain identity and explains to the person that he'll give them the ability to accomplish their goals, if in turn, the person will retrieve the Ladybug Miraculous and Cat Miraculous from Ladybug and Cat Noir.

When the person agrees, black and purple smoke appears from the possessed object and surrounds the person. Once it recedes, the victim has transformed into a supervillain. If Hawk Moth needs to telepathically talk with them again, his light mask will reappear on both Hawk Moth and the villain.

While it is theoretically possible for someone with extreme willpower to resist or even overcome Hawk Moth's influence, it is very rare.

Abilities
An akumatized villain usually has an appearance and abilities that relate to their infected object, occupation, circumstances, and/or interests. For example, because of Katie Morris's love of Queen Ven and all things alien or space related, he becomes Princess Cosmic, a villain with a crystal suit and a queen crown. In whatever way they're changed, an akumatized villain usually has enhanced abilities and skills. A majority of the time, their objects end up becoming their weapons.

Aside from their peculiar powers, supervillains seem to have enhanced strength, durability, and fighting skills.

Every villain, after being corrupted, remembers the cause of their distress and the person who caused it, so they usually try to get revenge. Every villain, after being corrupted, remembers the cause of their distress and the person who caused it, so they usually try to get revenge. Additionally, some villains, namely Gentlemanbug, remember the people whom they have romantic feelings for (Ladybug) and still care for them while transformed.

Hawk Moth can't mind control his villains, psychologically manipulating them instead. However, if a supervillain doesn't go and retrieve the Miraculous like they were asked to, Hawk Moth can control their bodies for a brief amount of time in order to inflict pain onto them until they agree to do it as quickly as possible. He can also remove their powers, another threat he uses against his victims to keep them on-task.

If Ladybug doesn't purify a villain's akuma when she captures it, the akuma multiplies, and they transform various people into frozen copies of the villain. When the original akuma's victim is akumatized again, the copies unfreeze, and the villain has control over them, able to make them follow his or her orders and desires.

Because of Hawk Moth and the villain's mental connection, the villain can sense the location of Hawk Moth's lair if they want to find him.

It's revealed that this mental connection is depended on proximity. If the Butterfly Miraculous holder is too far, they can't control the akumatized person or see and hear through them.

Defeat
After the Miraculous Ladybug has reverted the damage caused since the akuma infected the villain, they are de-transformed by the purple substance.

Those who are victimized will have their memories either be blurry of what happened (like a dream that can't be remembered), or can remember what had happened entirely. However, those who volunteered will retain clear memories of their actions.

List of akumatized villains
To see each villain's akumatized object, see List of akumatized objects