Serpent

Serpent (セルパン) was the antagonist of Mega Man ZX. He is the Model W Mega Man and the president of Slither Inc., a company which specializes in the excavation of ancient technology such as Biometals.

Appearance
Serpent is a large, muscular male Reploid. He has fair skin, violet eyes and hair, with a long spiked forelock. His face is distinguishable by the wide squared chin and slightly pronounced cheekbones. His outfit resembles an armored business suit, made of a long green jacket decorated with golden trim, blue gems and metallic shoulder plates, complemented by a violet cravat. His legs are covered in thick black armor, with golden plates around the ankles and white for the feet.

Personality
Although Serpent is considered a hero by the people, he is in fact a corrupt man that achieves his goals by any means necessary. He believes in survival of the fittest and that evolution and progress require sacrifice, which is rooted in his past as raid survivor and member of the Guardians, as well as the influence of Biometal Model W. Aile accuses Serpent of acting out of fear of his past and what he had become, while Prometheus claims that Serpent's will is too weak to handle Model W and his soul will be slowly consumed with time. His reaction when being fused with Model W has him grinning while being enveloped by Model W's energy tendrills and then cackling, implying that he was also insane.

Background
At some point in the past, Serpent survived a Maverick raid and joined the Guardians. He was a member of the recon unit led by the first commander that discovered and researched Biometal Model W. However, Serpent became obsessed with the Model W and this eventually drove him to madness, causing him to annihilate the entire unit to claim Model W and presumably gain his Mega Man Model W form as a result of the carnage (although the commander managed to escape and seal the Model W core in Area M).

After taking measures to prevent any information about his past from leaking, Serpent used ancient technology to found Slither Inc. and solve an energy crisis, gaining reputation as a national hero. He was eventually approached by Prometheus and Pandora, who told him about the Game of Destiny and the true power of Model W. Serpent then planned out Project Haven, which consists of staging Maverick raids throughout the years to gather the Cyber-elves of the terrified victims to feed Model W. While also searching for the Model W core, he comes into possession of Model H, Model F, Model L and Model P, employing them in the creation of Pseudoroids to further his plans.

Mega Man ZX
Serpent first appears during a Maverick attack on Area D, having subdued Girouette near the Slither Inc.'s head office. He uses his influence to turn Girouette against the Mega Man Model X (Vent / Aile), making them fight each other. As Giro attempts to resist Serpent's control, Serpent eventually strikes down the two Mega Men, calling them "disappointments" as he orders Pandora to steal the passwords to Model W's seal. He then leaves the two Chosen Ones for dead, deciding to continue his act as a public hero while the Mavericks and Pseudoroids do the dirty work.

However, the Model X Chosen One survives the incident and combines the power of Giro's Biometal with Model X to become the Mega Man Model ZX, using this power to defeat Serpent's Pseudoroids one by one. Serpent then sends Prometheus and Pandora along with a Slither Inc. fleet to destroy the Guardians, but the attempt is again thwarted by the Mega Man ZX.

Serpent later appears in Area M, briefly confronting the Mega Man ZX before escaping with the Model W core while Pandora fights the Chosen One. He then starts a final Maverick assault on Area O to collect more Cyber-elves, which is again stopped by the Mega Man Model ZX, who takes the fight to Serpent himself in Slither Inc.'s head office. During the confrontation, Serpent feeds the Model W core with the harvested Cyber-elves and uses Model W to Megamerge. As the two Mega Men battle, Serpent reveals the final key to his plan; to harnesses the hatred of the Mega Man ZX for him and use it as the final sacrifice to Model W, fusing with it to become a powerful robot. However, Model W's resurrection is short-lived, as he is defeated again. He then tells Vent that he is a maverick in response to the latter's statement that Serpent is a maverick, and also implies to Aile about her blood transfusion from Master Albert that allowed her to become a Mega Man. As Serpent dies, he declares all of humanity to be Mavericks for stopping progress, and for possessing the wellspring of emotion such as the heart, and thus having hate, and also implies that the destiny of destruction has yet to arrive.

Mega Man ZX Advent
Serpent is briefly seen along with Vent, Aile, Girouette, Aeolus, Atlas, Thetis and Siarnaq in an image from one of Biometal Model A's ciphers (code UC80 to AC195), which reveals to the Model A Chosen One (Grey / Ashe) that every Mega Man received the DNA of Master Albert.

Mega Man ZX (Manga)
Serpent reprises his role as the villain in the manga by Shin Ogino. After Vent combines Model Z with Model X to perform the Double Megamerge, Serpent decides to deal with him before he becomes too "troublesome". He is enraged when Hivolt and Lurerre are both defeated by Vent, and orders Prometheus and Pandora to destroy the Guardians backing him up. Although the attempt fails, the Guardian Base is disabled and Serpent starts Project Haven, sending a Maverick army to attack the city while the frightened people are captured to feed Model W with their negative emotions.

After Prometheus tricks Vent into using his rage to restore Model W, Serpent uses the Biometal to Megamerge and fight Vent. However, just as he is about to deal the final blow, Sho brings Model H, Model F and Model L, which were damaged in Vent's earlier battle against Purprill. Serpent blasts Sho away, enraging Vent who in turn uses all the Biometals to gain the upper hand. But the situation changes when Vent's rage fuels Model W further, transforming Serpent into a giant robot. Claiming to have the power of a god, Serpent nearly defeats Vent, but he falls when the positive emotions of the people are channeled into Vent, giving the Mega Man Model ZX the power to defeat Serpent.

Biometal Form
Serpent uses a fragment of Biometal Model W to Megamerge and fight the player. This form has orange horns emerged from the shoulders, feet and head, the whole body is covered with a black/white armor with yellow lines run across. This form was also earlier foreshadowed in one of the Guardian recon unit's reports, when mentioning that he became "something else" shortly after betraying them and stealing Model W. His arsenal include mostly increased physical attacks (uppercut, kicks), shooting from fingers, large energy balls, and an Overdrive that increases the velocity of his attacks, with a large variety of moves:
 * Gauntlet Swarm: Serpent fires five energy bullets from his fingertips simultaneously. He can do it in the ground and in the air.
 * Slide Kick: Serpent slides across the floor with his foot forward.
 * Sky Uppercut: Serpent kicks upwards, jumping high enough to reach the top of the screen.
 * Earth Crusher: Serpent phases to the top of the screen and drops on the player with his foot charged with energy; impact causes energy sparks to fly across the field.
 * Phase Sphere: Serpent charges a concentrated energy sphere with his fingertips and fire it towards the player. If the sphere takes enough hits, its polarity reverses and damages Serpent instead.
 * Overdrive Invoke System: Creates a resonating aura that increase the velocity and accuracy of his attacks.





Ultimate Form
Serpent fuses his body with the awakened Model W core for the final battle. As each of his health bars is depleted, his body continues to transform, changing his weak point and giving him new attacks.

Initially, Serpent's head is vulnerable, and he has three attacks of his own:
 * Chaos Meteor: The orange horns on Serpent's head and shoulders fire beams at the top of the screen; a moment later, four blazing rocks fall across the field. The meteors set parts of the ground on fire and leave eight small fireballs in their wake, which slowly home on the player.
 * Crystal Break: Serpent's hands fire purple lasers straight below themselves, producing clusters of purple crystals on both corners of the battleground. The boss uses his claws to shatter the clusters in an attempt to hit the player with the shards.
 * Atomic Pulses: Serpent spits green energy balls at the player, which split into two diagonal beams on contact with the floor. If struck in the air, the balls will split into four diagonal beams.

Console Phase
After losing his first bar of health, Serpent gains a green, eye-like projector on each shoulder, and his upper body rises upward to expose an opening in the middle of his body. His shoulders are vulnerable to attack and he loses his Crystal Break, but he gains three new moves to use against the player:
 * Dark Vortex: A purple vortex forms in the opening below Serpent's chest, which draws the player towards it.
 * Dark Debris: After the previous attack, Serpent fires several small purple particles in a random pattern from his stomach. The particles temporarily slow down the player on contact.
 * Tractor Shots: Serpent's shoulder projectors shoot two cursors that follow the player. If the player is hit, their HP will be drained and absorbed into Serpent's HP bar.

Redeemer Phase
Once reduced to his final health bar, Serpent deploys a set of large, free-floating hands and rises even further from the ground to expose a red and purple lower body. The panels on the front of his lower body reconfigure into a giant face, and the golden armor on its "forehead" retracts to expose a green crystal. Said crystal is Serpent's new weak point, but its armor will periodically cover it for brief periods of time. The player will have to time their blows to strike the crystal when it is vulnerable, while also dodging Serpent's attacks.

Although Serpent abandons his Chaos Meteors and Atomic Pulses in his third phase, he retains all of the attacks introduced in his second phase, which have increased chances of hitting the player due to his height increase. His new hands restrict the player's movement to the middle of the battlefield and inflict damage on contact. Additionally, Serpent's final phase also gains two dangerous new attacks:
 * Light Barrage: Serpent's fingertips and green helmet horn fire a series of green energy circles aimed at the center of the field. He will usually fire two or three waves of circles.
 * Crystal Crash: Serpent's second set of hands fire purple beams into the center of the screen, creating a spherical mass of crystals. The hands proceed to smash the crystal between themselves, sending multiple shards flying across the room. To complete the attack, the clasped hands slam into the ground.before separating and returning to the sides of the screen.

Trivia

 * It should be noted that Serpent was not necessarily evil, as it is suggested that Model W drove him insane. He believes he is doing the right thing, because in the final battle he states he wishes to evolve the world rather than destroy it, and in Vent's story, he states that he wishes to remove all the pain and suffering. In the end, it was his own doing that undid Slither Inc..
 * Serpent is a word of Latin origin that is commonly used in a specifically mythic or religious context, signifying a snake that is to be regarded not as a mundane natural phenomenon nor as an object of scientific zoology, but as the bearer of some symbolic value. Serpents are also connected with renewal or regeneration, so it can be said he was named this because he wishes to destroy and evolve the world.
 * Serpent shares many similarities to Sigma: both were originally members of a protection force, both were corrupted by a villainous source, both have ideals of evolution and both are the antagonists of the games they appear in. Serpent also physically resembles Sigma, although he is distinguished by a peculiar hairstyle and lacking scars on his eyes. Both characters even used the line "evolution requires sacrifice" at one point.
 * It can be assumed that Pandora and Prometheus were controlling Serpent the whole time because he seems calm, but when Pandora and Prometheus were not with him (or in close proximity, as shown in his taking Model W), his composure was lost and didn't know what he was doing. This is also implied by some Slither Inc. employees when they said that Slither Inc's way of operation changed as soon as Prometheus and Pandora began to work there.
 * Serpent's Redeemer Phase greatly resembles the Devil Gundam, the main antagonist of the 1994 anime Mobile Fighter G Gundam.  Model W's properties in general are very similar to those of the Devil Gundam.
 * While Serpent's Ultimate Form changes its weak point over the course of the fight, all phases are highly vulnerable to Model HX's Tornado charge attack.
 * The final phase of the Serpent battle bears some resemblance to the final phase of the Ursula battle in the video game adaptation of Disney's The Little Mermaid due to their growing giant. Both the video game adaptation of The Little Mermaid and Mega Man ZX are made by Capcom.