Beta Ray Bill

Origin

When Surtur destroyed the Burning Galaxy on his crusade to destroy Asgard, a race of beings called the Korbinites left their planet in a massive fleet. Before the journey, however, their scientists created a guardian who would travel with the fleet and protect them during their journey. Their first guardian, Alpha Ray, was riddled with problems. He was a mindless automaton, and deemed too unstable in both body and mind to be their protector. His body was put into stasis in a Meta-Orb and the Korbinite Bill was selected after various tests and challenges and was turned into a cyborg. When the Korbinite fleet neared the Milky Way Galaxy, it was detected by a SHIELD satellite and Nick Fury asked Thor to investigate. When Thor arrived in the vicinity of the fleet, Bill's sentient ship, Skuttlebutt, detected him as a threat and opened fire. Thor boarded Skuttlebutt and he and Bill fought. During the fight, Thor lost his grip on Mjolnir for more than 60 seconds and was transformed into Donald Blake. Curious, Bill picked up the hammer and was deemed worthy, instantly giving him the powers of Thor and a costume of similar design.

Stormbreaker

Sensing this, Odin transported both Thor and Bill to Asgard, where Bill demanded he be allowed to keep the hammer because he had beaten Thor. However, Odin said that the contest was not fair because Thor had an artificial limitation, so he temporarily restored both of their powers and arranged for them to fight to the death in the realm of Skartheim, a lava-filled wasteland. After a long and grueling battle, both combatants succumbed to exhaustion and collapsed. However, Bill's race was naturally enhanced by warm climates and he awoke before Thor but refused to take his life, thus passing Odin's final test.

Odin then created a new hammer, Stormbreaker, imbuing it with all the powers of Mjolnir, but none of the limitations. Thor and Bill became friends and they, along with Sif, returned to save his people from the armies of Surtur.

Though Thor was called back to Asgard before the Korbinites were safe from Surtur's minions, Sif stayed with Bill to continue fighting the demons and because she was curious about him. It was during this time that she learned from Skuttlebutt the extremely painful and difficult trials Bill had to undergo to become the guardian of his people and that he was the only survivor from many volunteers. When Surtur finally arrived at Asgard, Sif and Bill were called back by Odin, and they were placed in charge of leading the Asgardian army on Earth while Thor and Odin fought against Surtur's army in Asgard. 
 
During the battle, Odin hurled Surtur and himself into a fissure in the ground, seemingly killing them both. Thor, unable to accept his father's death, refused to lead the Asgardians and asked Sif to lead them in his stead as he began a journey to find Odin's spirit. Sif asked Bill to stay in Asgard and help her lead the Asgardians during their recovery from the war with Surtur. During this time, Bill and Sif became very close, and a romantic relationship was hinted at but never realized before Bill eventually left to return to his people.

Beta Ray Bill as the cosmic-powered version.

Bill disappeared from the comic scene for a while, until a mad scientist tried to poison the World Tree, Yggdrasil, in order to bring about Ragnarok early so that he could see the new life forms it would create. Because of this, the Asgardians began to weaken and die. Since there could only be one Thor when Ragnarok came about, the tree sent large spiders to bite and poison Bill. 
 
To save his life, Odin and the Silver Surfer merged the Odinforce and the Power Cosmic into a new energy source, restoring Bill's power, along with a new costume and hammer. Bill went on to become a member of the Star Masters along with Silver Surfer, Quasar, and others. Eventually, Thor stopped the poisoning of Yggdrasil and restored the Asgardians. Stormbreaker was restored along with the rest of the Asgardians and Bill returned to his original costume.

Ragnarok

Bill was left floating in space, unconscious as Galactus devoured New Korbin. Bill was awakened by Skuttlebutt to fight Stardust and protect his people's Meta-Orb. Stardust countered the attack by opening a portal to another dimension to banish Bill, unintentionally setting loose a powerful demon, Asteroth, in the process. Bill and Stardust were forced to work together to defeat Asteroth. Galactus took the lifeless body of Alpha Ray and gave it a portion of the Power Cosmic, and sent it to assist Stardust and Bill. Stardust opened a black hole behind Asteroth, but instead of sucking her in she redirected the force and started to pull them in. Alpha Ray arrived just in time to ram into Asteroth, sending both Asteroth and himself into the Black Hole.

Afterwards Bill returned to Asgard with the Meta-Orb containing the souls of his people. Bill arrived in ruined Asgard hoping that the Asgardians had returned and would be able to restore his people to life; but, the meta-orb had been corrupted by Asteroth and spawned a demonic version of Bill. Calling itself Omega Ray, the creature claimed to have feasted on the souls of the Korbinites. Enraged, Bill grabbed Omega Ray and called down an immense amount of lightning, killing them both.

However, a white-cloaked figure took the remaining souls of the Korbinites and told Bill that it wasn't his time to die. He awoke on Earth in the body of a human named Simon Walters. After wandering for a time, Bill came upon Spider Man fighting a villain. Slamming his fist on the ground, Bill was transformed into his Thor-like self, with Stormbreaker in hand, and helped Spider-Man defeat the villain. Bill then left to go and seek his new place in the universe.

Recently, Bill found himself drawn to the Royal Ontario Museum in Toronto by a series of strange visions. Arriving there, Bill was astonished to see the Wrecking Crew open up a portal to the Realm of the Great Beasts, acquiring the power of Tanaraq and unleashing a horde of Surtur demons onto Earth. Transforming back into his true form, Bill joined forces with the Canadian super-hero team Omega Flight to fight the villains. In the end, Bill sacrificed himself to save the planet, luring the demons back into the Realm using Shaman's medicine bag, which contained the essence of Tanaraq drained from the Wrecking Crew. With the portal destroyed behind him, Bill is now trapped in the Realm of the Great Beasts and fights an unending battle against the merciless Surtur hordes, imprisoned but unconcerned with his eventual fate.

Secret Invasion

By some unknown means, however, Bill was drawn from the Realm of the Great Beasts by the malevolent Skrulls, who captured and tortured him in order to replicate his powers for their Super-Skrull warriors. During this period, Stormbreaker was taken from him to be used by one of the most powerful "Godkiller" Super-Skrulls, before the weakened Bill was cast down to Earth to the location of the restored Asgard, bringing with him a warning of the ensuing Skrull invasion and their ultimatum to leave Earth or be destroyed. Granted Thor's hammer Mjolnir, Bill and Baldur led the defense of Asgard against the "Godkiller" Super-Skrulls while Thor remained in his human avatar of Donald Blake to assist the residents of neighbouring Broxton. Weakened in the fight with the leader of the Skrull attack force, Bill eventually gave the hammer back to Blake, who has Thor, defeated the Skrull and restored Stormbreaker to him, with their combined powers able to destroy the Skrulls once and for all. After the battle, Thor departed to New York to assist the other heroes in defeating the primary Skrull army, while Bill left for the stars, hoping to take his revenge upon the surviving Skrulls for his ordeal.

The Green of Eden and Godhunter

Following his departure from Earth, Bill found himself aiding a group of breakaway "Godkiller" Super-Skrulls, who had survived the battle for Asgard and abandoned their previously militaristic ways. Pursued by a band of Skrull warriors loyal to the jihadist mission of Queen Verenake, these refugees sought out Bill, as they had become inspired by his valiant defense of Asgard and saw him as a figure worthy of becoming their new god. Somewhat shaken by their obedience and devotion and still grieved from the loss of his people at the hands of Galactus, but aware that the hearts of the Skrull refugees were in the right place, Bill ultimately declined their worship, simply telling them to "make good."After defeating their pursuers and sparing the life of the Super-Skrull sent to kill them, Bill returned to Earth with Skuttlebutt, hoping to find his own measure of peace.

Bill continued to destroy planets in Galactus' path and continued to starve Galactus. But he soon found he was unworthy of lifting Stormbreaker for the despicable act of giving the planet's populace a deadly disease. He donned the weapons of Voidian for a final assault on Galactus. But when he arrived, he found the infected aliens about to do the job for him. In a last minute change of heart, Bill defended Galactus from his attackers.

Bill explained to Galactus that his people would not wish their legacy to be so stained with blood. Having fed, Galactus took the spirit of a Korbinite that still lingered in the universe and created a new body for it. Bill now had a female of his race to repopulate their species. Bill and his new mate, Ti Asha Ra, were finally at peace.

Powers

Bill is a cyborg Korbinite, making him stronger, tougher, and faster than other Korbinites, who are in turn much more powerful than baseline humans. His cybernetic form, along with his combat prowess (See Below) granted him the ability to match Thor in hand-to-hand combat.

With Stormbreaker, Bill possesses all the powers of Thor's hammer, Mjolnir, and is his physical equal. He can control weather, create blasts of energy, absorb and rechannel energy, fly, teleport, and sense power sources. He can fly, even through space for long periods of time without the need for air. Stormbreaker will return to Bill if he throws it and is nearly indestructible. He does not, however, possess the abilities innate to Thor's unique heritage, such as the God Blast, Warrior's Madness, and Rune Magicks. Bill has not demonstrated some of the finer and more exotic abilities with his hammer that Thor has, but whether this is by choice or due to lesser experience with that power remains to be seen.

Beta Ray Bill is naturally enhanced by warm climates.

Combat Abilities

Bill was chosen as the guardian of his race by becoming the best gladiator on the entire planet. Making him one of the greatest warriors in the known galaxy when it comes to unarmed or melee combat. This gladiatorial training/experience made him capable of matching Thor in hand-to-hand combat.