Galactus (Earth-666398)

"I am Galactus, Devourer of World! Kneel or have your world be devoured like the rest!!"

- Galactus's arrival Abraxas Galan (better known as Galactus) is a malevolent cosmic entity older than the current Marvel Universe and the main antagonist of the Dark Avengers: Devourer of Worlds. He was once a scientist that was ascended to a higher plane of existence. Using his new found powers, Galactus destroyed his own universe and created the Marvel Universe in hopes of creating a "Perfect Universe freed from any signs of flaws" but saw that universe as imperfect as well. He attempted to destroy the current universe but was stopped by the other cosmic entities.

He lost some of his powers which forces him to keep on devouring planets to regain them giving him the title "Devourer of Worlds". Enslaving those he considered to be his new "Heralds", Galactus sought to become all-powerful by remaking the universe in his image.

He is the founder and patron deity of The Children of Abraxas (Which is lead by Thanos himself) who fanatically follow the evil god in his omnicidal quest. Being a sadistic, power-hungry, remorseless, arrogant and egotistical deity that enjoys pretending as if he was a supreme being. He also has devoured gods before he was stopped by Celestials and Eternity. He serves as the archenemy of the Silver Surfer, being the one who killed his family and brainwashed him into being one of his heralds.

Backstory
Abraxas Galan was a amoral and nihilistic scientist prior to his ascension to godhood or the creation of the current universe. Galan despise the creatures around him, including his own people and even intelligent life itself as he sees life as flawed and imperfect. Galan used the cosmic egg to make himself a god and gain god like abilities called "The Power Cosmic". He uses his new found powers to destroy his universe with life in it, leaving no survivors. He started to create a new universe- The Marvel Universe- In his image until he sees that universe as flawed and imperfect as well. However he was opposed by the Cosmic Entities (Led by Eternity) in a cosmic war that lasted for about an eon. Galan enslaves the Skrulls and the Chitauri for his war, while enslaving planets so tat he could turn others into his heralds so that they would be forever loyal for him until death.

He was eventually defeated by the Cosmic Entities but survived the war and escapes from punishment. However he lost some of his powers after the war, so in order to gain them back he has to devour the life essence of each planet he comes across in the universe. Now renaming himself Galactus, he soon have his heralds invade planets and slaughter those who try to prevent him from devouring their planet. One day he comes across the planet Zenn-La which inhabitanted a race of civilized humanoid aliens. However the planet was protected by Celestial technology given to them by The Watchers. So Galactus possessed Eran Radd, father of Norrin Radd, and have him deactivate the shields to allow him to enter the planet. Galactus has Tyrant, his first creation, to mercilessly destroy the cities of Zenn-La. Galactus spared Norrin Radd only so he could turn him into one of his heralds, he renames Norrin into the Silver Surfer and wipe his memory clean to make it look like he serve Galactus from the very beginning.

Finding the Children of Abraxas
Galactus finds Thanos, a titan who was obsessed with nihilism and death, on the planet called Titan and convinced him to worship him with the promise of becoming a god like him. Thanos formed the  Children of Abraxas to worship Galactus and bring death and chaos in his name. Thanos destroyed his own planet in Galactus's and raised an army of his own.

Discovery the planet Earth
Through many centuries, several planets has fallen to the might of Galactus. However one of his heralds discovered the existence of the planet Earth but his herald was somehow was badly damaged (the herald battled Thor by the time she found the Earth) and died from her injuries. Galactus orders Thanos to find the planet Earth and "prepare" it for his coming arrival.

Personality
"Our master Galactus is the embodiment of death, destruction, and nihilism. He understand us and our motives. We hate this reality, so he seeks to bring a better one. A universe without flaws, without imperfection. We are his heralds, we are the Devourer's will and we shall be his wrath if you dare to stand in his way."

- One of Galactus's heralds on the motivation of Galactus. Galactus is a power-hungry, nihilistic, and immensely cruel deity obsessed with making a perfect universe freed from flaws. Being the personification of a egotistical control freak, Galactus shown to be flawed himself-Showing signs of overconfidence as he claiming that no mortal or lesser deities have ever harmed him nor ever will, despite the Avengers and the Fantastic Four using the Cosmic Nulifier to harm him. He is has a massive ego and possess a god complex, saying he is the god of everything that exist in the multiverse only to proven wrong when the One-Above-All appears. Galactus shows symptoms of sadism as shows great pride on remorselessly destroying planets and devouring their  life forces as he claims he is "punishing" the impure. However Galactus does show mercy, albeit a twisted sense of the word, as he spared Norrin Radd's life only to turn him into one of heralds who acts as slaves to the Devourer.

True to what his cultists say about him, Galactus is the absolute embodiment of death and destruction, but unlike the other destroyer gods who brings destruction for a necessary cause, Galactus does it for his sheer nihilistic and sadistic desires to bring a universe where he shall rule as an unopposed Supreme-Being. He is very wrathful on those who tries to get in his way, as he would not hold back on those that pester him. Galactus is very intelligent, as he orchestrated the many atrocities caused by the Children of Abraxas and Thanos like the mass destruction of the invasion on Earth (Though Doom was the one that summoned Thanos for his own ambitions). He also manipulated Thanos, a super intelligent alien, into being one of his servants proving that he is a exceptionally manipulative mastermind. He shows traits of Psychopathy- He completely lacks a conscience, fear, remorse or empathy is extremely narcissistic and arrogant.

Though despite his overall malevolent nature, he doesn't see himself as good or evil. He see himself as above morality or mortal judgement, this mainly coming from his massive ego and narcissism. He uses this belief to his followers so that they won't judge him or question him.

Trivia

 * This Galactus took some characteristics from Marvel's Abraxas and the Marquis of Death.