Zs'Skayr

Zs'Skayr (pronounced Zuh Scare,) also known as Ghostfreak, was the Ectonurite High Ecto-Lord of Anur Phaetos and Anur Transyl. He was originally stuck in the form of Ghostfreak, but after time managed to gain control over it and escape the Omnitrix, becoming one of Ben Tennyson's most dangerous enemies.

Past
Originally, Zs’Skayr was High Ecto-Lord of the Ectonurites of Anur Phaetos and learned of the Omnitrix from the data of a probe belonging to Vilgax that crashed on his planet. Soon afterwards, Zs’Skayr met Myaxx as she was seeking DNA samples and helped her to get some from the nearby planet, Flors Verdance. But unbeknownst to her, the Ectonurite took over the Flourana being sampled, thus she took an Ectonurite sample as well. Since Ectonurite’s personality and DNA were tied together, Zs’Skayr’s personality then formed in the Codon Stream even after the real one died. A clone of the Ectonurite was then born inside Ghostfreak.

Ghostfreaked Out
After Ben Tennyson gained the Omnitrix, Zs’Skayr’s personality became present whenever he turned into Ghostfreak. After some time, Zs'Skayr finally freed himself of the Omnitrix and confronted Ben, tearing away his outer layer of skin to reveal his intimidating, true form. Wanting to become whole again, Zs'Skayr attempted to possess Ben, but failed to after the sun drove him back. He sought out the Circus Freak Trio and got them to aid him by threatening them when he took over Thumbskull and tossed him around the room. Zs'Skayr went with the trio to confront Ben and tried to possess him, but since Ben had been changed into Four Arms at the time, he couldn't do so. The Ectonurite took over the Circus Freak Trio to fight Ben, but they were defeated one after another. However Zs'Skayr took over Gwen and used her to fight Four Arms, who eventually regressed back to Ben. The Ectonurite then threatened to make Gwen jump off of the wall they were fighting on if Ben didn't give up. Ben agreed and Zs'Skayr sent the Circus Freak Trio after Gwen and Grandpa Max, before trying to possess the boy. However Ben was able to transform into Grey Matter just in time and Zs'Skayr continued to pursue him. Eventually Ben changed back to normal and the Ectonurite prepared to again try and possess the boy. However he noticed that it was daytime outside and opened the curtains on the building they were in, destroying Zs'Skayr.

Be Afraid of the Dark
However Zs'Skayr was not finished yet and a Transylian scientist from the Anur System named Dr. Vicktor began working to revive him. He stole material from the clock tower where Zs'Skayr had been destroyed and gained the help of a Thep Khufan and a Loboan from the Anur System. As well as bring back Ghostfreak, Vicktor prepared to plunge the Earth into complete darkness for his master to rule. Onboard a NASA Space Shuttle, Vicktor revived his Ectonurite master to face Ben Tennyson again. Then with Corrodium that the Thep Khufan had retrieved, Zs'Skayr and his minions then used a Corrodium beam, blocking out all light from the Sun. With the Earth consumed in eternal darkness, the Ectonurite was fully empowered, but this didn't last long. Vicktor was tricked into destroying the Corrodium beam and Max opened the space shuttle’s roof, exposing him directly to Earth’s sun and destroying him again. At the same time, Ben managed to regain Ghostfreak on the Omnitrix, but ended up never using him.

Alien Force
Zs'Skayr was eventually removed from the Codon Steam and imprisoned using sunlight by the Galvans. However Vilgax freed him in exchange for the secrets of the Omnitrix and the knowledge that would let him finally beat Ben. Zs'Skayr told him about Primus, the location of the Codon Stream, but as soon as Vilgax freed him, the Ectonurite betrayed him. Zs'Skayr took over Vilgaxia, Vilgax’s home planet, by possessing the citizens, transforming them into Ectonurite creatures. Vilgax tried to fight them, but was forced to retreat and went to Earth to ask for help from Ben, Gwen, and Kevin. They went to Vilgaxia and infiltrated Vilgax’s palace where they found Zs'Skayr, who revealed that Vilgaxia was just the beginning and his minions were already building ships to spread their master’s influence to other planets. The Ectonurite possessed Ben, which was actually part of his plan since it trapped Zs'Skayr back in the Codon Stream. Ben transformed into Ghostfreak, but the Ectonurite quickly took control and began fighting Gwen, Kevin, and Vilgax. Eventually Gwen and Kevin were knocked out and Zs'Skayr managed to knock Vilgax’s sword away. He made his minions restrain the conqueror so the Ectonurite could possess him as well. But Vilgax freed himself and used light from his sword to weaken Zs'Skayr, letting Ben regain control and change back, trapping the Ectonurite back in the Omnitrix.

Omniverse
Zs'Skayr makes his return in "Mystery, Incorporeal", being seen crawling out of the portal to Ledgerdomain. According to himself, Ben left him trapped there, and Darkstar opening the portal allowed him to escape. Derrick J. Wyatt states that after Ben destroyed/dispersed him in their last battle, Zs'Skayr used the magic of Ledgerdomain to reform himself there.

In "Rad Monster Party", he along with Dr. Viktor, Kuphulu and Crüjo attempted to defeat Ben and his team, only to be defeated by NRG. His main objective was to regain his title as High Ecto-Lord.

In "Charmed, I'm Sure", he has drained a large portion of energy from the Alpha Rune. Though he thinks it is completely powerless and is now useless, that is not the case.

In "The Vampire Strikes Back", Zs'Skayr used the power he had drained from the Alpha Rune in order to ressurect Lord Transyl, and create a powerful servant in order to regain his title as High Ecto-Lord. This was against the objections of Dr. Viktor, who remembers how Lord Transyl's race had enslaved his people. Ultimately, Zs'Skayr's plan comes to naught as Viktor betrays him and he is once again burned to ashes, this time by Ben as Atomix while he is seemingly killed, Ben stated that he will return some day, So he leaves a light fusion orb called "Fusion Cuisine" in Zs'Castle Zs'Skayr so Zs'Skayr could not get in.

Protector of the Earth
In the video game, Ben 10: Protector of the Earth, Zs'Skayr freed Vilgax from the Null Void, joining forces to have revenge on Ben. He also took over Hex so as to use his magic as a means of summoning his minions from the Anur dimension. Ben managed to stop this and Zs'Skayr left Hex, attacked the boy again in Chicago. However the Ectonurite was defeated again and banished to the Null Void.

Vilgax Attacks
Needing to obtain the last energy core to destroy Vilgax’s Null Void Projector, Ben found out that it was in Anur Phaetos. However Anur Phaetos was not technically a planet, rather it was an alternate dimension he, Gwen, and Kevin couldn't access. Verdona managed to bring them to the Anur dimension, but accidentally split them up and Zs'Skayr revealed that he was still alive. He confronted Ben, saying he was most unwise to set foot in his homeworld and sent his minions after his enemy. Ben managed to fight them off and face Zs'Skayr himself, but defeated him using light.

Powers and Abilities
Because he is an Ectonurite, Zs'Skayr can turn invisible and intangible and fly, as well as possess other bodies, taking complete control of them. He can also use this to turn other beings into his Ectonurite minions, who can in turn, do the same to others. Zs'Skayr can also manipulate his density to make himself lighter or heavier, consume souls, survive in space, use telekiensis, fire energy beams from his chest, and attack with the tentacles coming out of his chest. As a resort of his true form, his intimidating appearance can easily unnerve individuals, also including the appearance of his head. Zs'Skayr's only weakness is bright light, sunlight in particular, but he can form a second layer of skin to protect himself by hiding his true form. He also wields a scythe and after spending time in Ledgerdomain, he has gained some magical abilities.

Trivia

 * Zs'Skayr's name is a corruption of the word "scary".
 * The way it's pronounced is like saying "the scare".
 * In both the original series and Ben 10: Alien Force no one called him Zs'Skayr - they only called him Ghostfreak.
 * His appearance in Alien Force had a few differences from his original one, such as more spikes on his body, fangs, a more exposed striped tail, and white claws as opposed to black. Zs’Skayr's voice is different too.
 * Ben finally learns Zs'Skayr's name in Rad Monster Party.
 * In the same episode he stated that he never answers to the name Ghostfreak and prefers to answer to his actual name.
 * In Vilgax Attacks, Zs'Skayr implies that he is undead ("Alive? Interesting word choice.", "Ben 10, as I live and breathe... not!"). However, according to Derrick J. Wyatt, Zs'Skayr is alive, but the Ectonurite concept of "life" is just very different from most sentient life forms.
 * The features on Zs'Skayr's face are placed so that his face looks like an upside down skull, also horrifying in appearance.
 * Zs'Skayr's appearance in Ben 10: Omniverse bears a striking resemblance to the Grim Reaper.