Darkseid

In the 12th episode of the 5th season of Justice League Unlimited, Lex Luthor attempts to bring Brainiac back to life, but instead brings back Darkseid. Darkseid has obviously been affected by Brainiac, as his physical appearance has changed to incorporate aspects of Brainiac. This "new" Darkseid has been dubbed by some people as "Brainseid". Brainseid retains Darkseid's motives to conquer Earth and obtain the Anti-Life equation, but is considerably stronger than before. After giving his "thanks" to the villains who freed him, he promptly reestablishes order on Apokolips and once again invade Earth. This time Superman finally cuts loose and overpowers him, until Darkseid uses his Brainiac given abilities, quickly taking the hero out. He is ultimately stopped when Lex Luthor gives him the Anti-Life equation. They both disappear afterwards.

Bio
Darkseid was, and still is, the ultimate enemy of Superman. Darkseid humiliated him, killed his friends, and turned him against his own for a short time, costing Superman more than just lives, but friends and the trust of the country as well. He had caused Superman to go rogue...

...then he came and asked him for help.

Brainiac was attacking Apokolips and none of their forces could keep him at bay. Darkseid requested Superman's help, but Superman refused. When Darkseid told him that thousands would die and the planet destroyed, Superman's only reply was a cold "Good." The Justice League convinced him to aid Darkseid, but the whole while he never trusted Darkseid--so when it was revealed later on that Darkseid was actually working with Brainiac, Superman wasn't surprised. The two caught Superman and attempted to kill him, but when the League, sans Flash and Green Lantern, came to the rescue, Superman escaped and had a show down with Darkseid. Had it not been for Batman's interference, Superman would have finished Darkseid off, but by using a boom tube, Batman pulled Superman back to the rest of the crew and Brainiac's station, with Darkseid on it, blew up.

It is unknown if Darkseid survived the blast, but being the god he is, it's not unlikely that he survived.

Power and Abilities
The beings of Apokalips call themselves gods and live in a realm called the Fourth World which is outside normal space and time. Their strength is due to their relative proximity to the Source, an energy which fuels the powers of the beings in Apokalips. The inhabitants of New Genesis are far more stronger, faster, smarter, and are said to be immortal.
 * Superhuman Strength: Uxas is a very powerful alien from the planet Apokalips. His strength easily exceeds 100 tons as he is one of the strongest characters in the DC universe. However, his strength varies on his incarnation. Despite his strength fluctuations, his strength alone is a force to be reckoned with. He can easily destroy colossal objects, overpower humans and far stronger characters especially cosmic beings, has the capability to bend and break any man-made material, lift massive objects, and easily demolish infrastructures. His strength is so great that he can easily overpower strong beings such as Superman and Wonder Woman in hand to hand combat. His powers are so great that he could destroy a Green Lantern Ring with his bare hands.
 * Superhuman Speed: Due to Darkseid's New God Physiology, he can think, react, and move faster than a well rounded Olympic Athlete who engages in everyday exercise. Although not as fast as speedsters such as Flash and Superman, he would often surprise his foes by appearing right behind them. It is said that he can react within microseconds.
 * Superhuman Stamina: Darkseid's tissues don't create fatigue toxins resulting in him having inexhaustible stamina.
 * Invulnerability: Darkseid is extremely resistant to most forms of physical and mental harm. Darkseid's full durability capacity varies depending on the incarnation. Overall, because he is a high-tier cosmic being, humans couldn't even begin to harm him, bullets bounce off him, rockets, bombs and lasers won't even leave a mark on him, and high-voltage energy emissions can't penetrate through him. He is completely immune to all earthly diseases and viruses. Despite his resistance, powerful beings like Superman or the Martian Manhunter can cause him great distress and pain. Also, materials forged from his home world can hurt him as well. He, like all New Gods, is vulnerable to Radion.
 * Immortality: As a New God, Darkseid has an extended lifespan which allows him to exist indefinitely. He doesn't age, wither, or degrade. He has been reduced to nothing before by the Spectre but it has been shown that he reformed his body shortly thereafter.
 * Omega Beams: Darkseid's most destructive use of the Omega Effect. He focuses this power as a form of concussion that fires from his eyes. He has complete control over it that he can change its path at will. He can make it travel in a straight line, curve, bend, or twist around corners. When it hits a target, it quickly reduces the target into nothing. His Omega Beams are proven ineffective against Wonder Woman's bracelets, as they were created from the Olympian Aegis. Nothing has been said to to survive the full Omega Effect except for stronger beings such as Doomsday, Superman, and Hank Henshaw.
 * Telepathy: Darkseid can easily read minds of others anywhere in the Universe. He can also attack them telepathically and invade their thoughts.
 * Mind Control: Darkseid can control the actions and perception of multiple individuals at once.
 * Telekinesis: Darkseid can mentally influnce the movement of other objects to move with the use of his mind.
 * Matter Manipulation: With the use of the Omega Effect, Darkseid can dissipate and disperse molecules from an object or organism. He can create life or erase them out of existence. He could also use it to control the internal reactions of an organism such as to de-evolve it.
 * Teleportation: Darkseid can teleport himself and other beings anywhere in the universe.
 * Size Alteration: He can easily manipulate his size, density and mass.
 * Omega Sanction: Probably one of the most disastrous effects the Omega Effect can give. It can be described as a living hell for it traps the organism in a series of alternate realities, each one worse than the previous.