Darkdeath Evilman

Darkdeath Evilman is the main villain from the Nippon Ichi video game Zettai Hero Project: Unlosing Ranger VS. Darkdeath Evilman.

Disgaea D2: A Brighter Darkness
His core evility is Final Boss Barrier which decreases the damage taken by 100% but the effect decreases by 10% with every hit accumulated. His three specials are Evilman Slash, Evilman Death Rave and Evilman Gigantus Ray.

Zettai Hero Project
Darkdeath Evilman is a "Demon General" and a powerful super-villain. He has been undefeated ever since his first appearance and killed every superhero he's battled, with his latest target being the Unlosing Ranger.

The player faces off against Darkdeath multiple times in the game (in various parody battles that are reminiscent of turn-based RPGs like Dragon Quest and Final Fantasy). The battle sequences slowly get more detailed, as the hero gets 'more support and sponsors'. Between the chapters of the story the main characters slowly learn about the origin of Darkdeath. He is the last rescue target, in the X Dimension stage.

The main cast also frequently runs into the robot he built, which is his image of what heroes are like. This robot, who simply calls himself 'Hero', is the cause of many of the problems that the cast has to fix. He preforms actions such as convincing a family to forget about one of their family members because he is incompetent, giving a girl a killer psycho robot, as she wanted to become a boss character, and sitting and watching a crime scene as 'there is a much higher probability that a hero will not come to the rescue then that he will'. These philosophies come from Darkdeath's view of true heroes, due to him rejecting their existance. He worsens most of the psychological problems the rescue targets face over the course of the story.

In truth, the Robot Darkdeath Evilman is piloted by the scientist of the same name. He was isolated in school and simply attended to make his father happy, being well aware of the fact that everyone talked about him behind his back. Because he constantly transferred schools, he never saw the need to make friends. Eventually, Evilman became the world's youngest nobel prize winner ever, but his intellect caused him to become the target of an evil organization. He was kidnapped, and a hero never came to his rescue. He thus began to deny the existance of 'True Heroes' but secretly wished to someday be saved. If any ending besides the good ending is reached, the robot explodes, most likely killing him. If the good ending is reached, he becomes part of the super hero team including Danger Cop Dangerama, Super Baby Estranger, The Unlosing Ranger (Pirohiko Ichimonji), and The Unlosing Ranger (Main Character).

Disgaea D2: A Brighter Darkness
Darkdeath Evilman appears as an unrecruitable postgame boss character in Disgaea D2. After defeating him, players will unlock the trophy, Weekend at Darkdeath Evilman's. He doesn't speak, however, which could mean that the fight is between Darkdeath Evilman's robotic shell rather than Darkdeath Evilman proper.

Disgaea 5: Alliance of Vengeance
A monochrome version of Darkdeath Evilman known as "Proto Darkdeath" appears as an unrecruitable boss character in Disgaea 5. He randomly appears in the item world, though a bill can be passed that forces him to appear immediately. Beating him will grant a large stat bonus to the item, as well as unlock the Unlosing Ranger Status trophy.

Trivia

 * In Z.H.P., all of his pieces of armor (Legs, R Arm, L Arm, Body, Head) can be stolen. Under the Armor is a figure identical to the Evil Hero. These items can be thrown into the spring in Spring Rooms to receive more powerful 'dark' versions of the items (one per Spring Room). Wearing all of his equipment will replace the background music with a final boss-esque remix of the main theme.
 * If the main character is of a high enough (stored) level, he can beat Darkdeath Evilman during any of the mandatory fights in between chapters. If done at any point besides the end, however, a humorous bad ending (usually involving the main character falling into a shady business or a Disgaea character destroying the world) will occur. Thus, if the main character is too powerful, he has no option but to choose the Run Command (which causes various calamities to befall him, such as slipping on a Banana Peel and receiving 99999 points of damage).