Darkseid (DC)

"I. Am. The. New. God. All is one in Darkseid. This mighty body is my church. When I command your surrender, I speak with three billion voices. When I make a fist to crush your resistance. It is with three billion hands. When I stare into your eyes and shatter your dreams. And break your heart. It is with six billion eyes. Nothing like Darkseid has ever come among you; nothing will again. I will take you to a hell without exit or end. And there I will murder your souls! And make you crawl and beg! And die! Die! DIE FOR DARKSEID!"

- Darkseid.

Darkseid is one of the major enemies in the Superman comics and media, a merciless tyrant and member of an extraterrestrial race of deities known as New Gods. He is widely regarded as one of the DC Universe's most powerful and malevolent villains of all time.

Origin
Darkseid was the son of a dictator who ruled over a horrifying planet called Apokolips. Darkseid killed his brother Drax in order to succeed him to the throne. Never trying to hide his cruelty and malice, he sought to conquer the universe and rule over all with an iron fist. His sadism is perfectly obvious from the brutal way he treats the residents and slaves of Apokolips.

Superman
Darkseid would make several at conquering Earth, believing it to hold the source of the Anti-Life Equation, which would give him dominance over all life. His plans were always interrupted by the Man of Steel.

Supergirl
In what is possibly his most sadistic move, Darkseid kidnapped Superman's cousin Kara-Zor-El (later known as Supergirl) and had her brainwashed to be his servant. Superman, Batman, Wonder Woman and Big Barda all team up and invade Apokolips. Superman fights the brainwashed Kara, Wonder Woman and Barda fight the Female Furies and Batman rigs several explosives that would destroy Apokolips. Darkseid, having no wish to lose his empire, agrees to release Kara. Immediately afterwards, he attacks Superman in Smallville and nearly kills Kara, but Superman forces him up against the source wall, where he is imprisoned and drained of most of his powers.

Final Crisis
Shortly after the Death of the New Gods story arc, it is revealed that the denizens of Apokolips have taken residence within several Earthlings. Darkseid himself has become a nightclub owner known as Boss Dark Side. When his current human body begins to age at a rapid rate, he transfers his essence to private investigator Dan Turpin. As Turpin is lured into a secret lab run by Darkseid's minions, we see that the Dark One has indeed taken root in Turpin's mind and is slowly eating away.

While the main members of the Justice League are called out of action, Apokolips manages to cause untold anarchy, killing and enslaving millions with the fully-formed Anti-Life Equation. Turpin, his skin now solidifying and cracking, has begun to resemble Darkseid, but his will remains his own. When he sees his reflection, however, he shows despair, knowing that the Dark One has already taken over and is just waiting for his submission. Eventually, Turpin comes to the conclusion that there is no hope, that Darkseid's victory is inevitable, so he surrenders his body and soul and allows Darkseid full control of the Earth.

Batman, having discovered a bullet that is lethal to the New Gods, confronts Darkseid and tells him that even though he is against firearms, he will destroy Darkseid once and for all. Darkseid threatens Batman with his Omega Sanction, to which Batman replies by pulling the trigger. Darkseid is left injured and Batman is sent back in time. Afterwards, Superman finds what appears to be Batman's charred corpse and is ready to kill Darkseid, when he realises that he would only be killing Turpin. Darkseid laughs at Superman, stating that Earth's greatest hero would become the enemy of humanity once he had assumed complete control.

At that moment, the two Flashes charged past Darkseid, followed swiftly by The Black Racer, the New God of Death. Darkseid is caught and purged from Turpin's soul. When the Justice League is tasked with removing all traces of Anti-Life from Darkseid's human minions, Superman is confronted once again by Darkseid, this time in spirit form. Superman erases him from existence by singing a note so high it could affect the immaterial. With that, Darkseid's reign of terror is ended.

New 52
Darseid appears in the new reboot of DC as the first threat the Justice league faces.

Superfriends
Darkseid is the main antagonist in the final 2 seasons of Superfriends. He has the Joker as his stooge to help him invade and conquer Earth. He is also obsessed with making Wonder Woman his queen, as like most villains that follow a certain "evil designs/plans" trope, he doesn't want to rule the universe alone. In fact, the very first episode of Season 5, The Bride of Darkseid, has him using a mind-control beam on her and explaining to her that he "chose her to be his queen".

Smallville
Darkseid is one of the main antagonist in the season 10 of Smallville.

DC Animated Universe
Darkseid's first attempt to attack Earth was by brainwashing Superman to do so, due to the New Genesis that protected Earth. However, Superman's will power was far more powerful than the mind control and broke free of Darkseid's manipulation, causing his plan to fail. Later, Darkseid's planet Apokolips was attacked by the Kryptonian computer Brainiac and Darkseid was killed in the process when Brainiac's base exploded. When Lex Luthor and the Legion of Doom tried to ressurect Brainiac, they unintentionally revived Darkseid merged with Brainiac who then launched an invasion on Earth. Superman beat him physically in Metropolis, but he soon trapped him and nearly murdered him with a Kryptonite knife. However, Lex intervened by using the Anti-Life Equation he found and used it against Darkseid, either destroying or absorbing him.

Batman the Brave and the Bold
In the episode "Darkseid's Descending" Darkseid sends his army to Earth where they fight the Justice League but quickly take over. They try to stop Kalibak and his army of Parademons from accessing a boom tube that would bring Darkseid from coming. They fail and he is able to come to Earth. He reveals that Batman is the first one to ever dodge his omega beam. Batman then uses his honor to his advantage by challenging him to a fist fight. He nearly kills Batman until he leads Darkseid to the boom tube and Question reworks it to transport him and his army back to Apokolips and then destroys it. In the episode "Powerless" after losing his powers Captain Atom tries to fight him in a training simulation but is defeated by Darkseid.

Young Justice
In the episode "Endgame" he is shown on Apokolips with Dessad and Glorious Godfrey. It is revealed that he and Vandal Savage are in cahoots and they now have possession of the War World.

Grudge
Darkseid has harbored a fierce hatred of Superman ever since he stopped him from conquering Earth. In Justice League: Unlimited, Darkseid was eventually killed by Superman, but then, brought back inadvertently by Lex Luthor. He, then, sought to get revenge on Superman by destroying the Earth and killing Superman.

Mortal Kombat vs. DC Universe
At the start of the game, Darkseid and his Parademons were defeated by Superman and his Justice League comrades. As Darkseid was about to flee through his dimensional boom tube, Superman hit his nemesis with a heat vision thus destroyed the boom tube and seemingly destroying Darkseid. But this was not the case, instead, Darkseid was fused with Shao Kahn after he was blasted by Raiden creating Dark Kahn. After Raiden and Superman defeated Dark Kahn, the worlds were separated and Darkseid awoke in the Mortal Kombat universe. Without any powers to protect himself, Raiden brought Darkseid before the Elder Gods for judgment and they sent him to the Netherealm.

Mortal Kombat Vs. DC Universe Ending
In his ending, Shang Tsung tried to steal his soul, a source of immense power, but the Apokolips ruler reversed the soul drain to reduce the sorcerer to an old man. This allowed Darkseid to break free and Shang Tsung offered his life and servitude to him so as to spare his own life.

Amalgam Comics
After the successful Marvel Versus DC crossover series the two companies ran a limited edition series of meta-fiction known as Amalgam Comics, in this series Darkseid was merged with Thanos to create a new character known as Thanoseid.