Easily the most famous of all the Green Lanterns, Hal Jordan first appeared in Showcase #22 all the way back in 1959. Since then, he's faced some of the worst villains that have ever featured in the DC Comics Universe, defending Sector-2814 with the help of his power ring and using his superpowers for the greater good.
He's fought former friends and lovers, galactic monstrosities, and even himself, but regardless of the threat he does whatever he can to save those he swore to protect, whatever the cost. Here are some of the greatest threats he's battled in the line of duty to date.
10 The Anti-Monitor
The very fabric of the universe is built from two forces: matter and anti-matter. Without a balance between the two, all life would cease to be. When the multiverse was created, so too were the Monitor and the Anti-Monitor. Each would be responsible for managing this balance, but the Anti-Monitor's greed saw him conquer the Anti-matter Universe then head to the other.
He was solely responsible for causing billions of deaths in the original Crisis on Infinite Earths event. He can consume all matter and anti-matter to alter reality, and has an army of Shadow Demons to destroy whatever he sees fit. A dangerous and powerful foe for Hal Jordan, the Anti-Monitor is not to be messed with.
9 Cyborg Superman
After a tragic accident in space, Hank Henshaw used the pod that brought Superman to Earth to create a cybernetic body to fix the damage that had been done to him. He became obsessed with killing Superman, but he also became an enemy of Hal Jordan.
When he teamed up with the alien Mongul, Coast City was destroyed, leading Jordan to become Parallax. Henshaw was defeated by Parallax at the Source Wall, but it wasn't the end of Cyborg Superman. He would return with the intent of destroying all life, but after using one of Henshaw's Highmasters, he was beaten once again. Like all good villains, though, it wouldn't be the last we saw of him.
8 Star Sapphire
Carol Ferris is the love of Hal Jordan's life, but for a time she was one of his sworn enemies. The Zamarons - a race of Amazonian women - used her to become Star Sapphire after she greatly resembled their last queen. Possessed by their sapphire gem on her head, she would be used to fight Green Lantern and achieve dominance for the female race.
Unable to defeat Hal Jordan, the Zamarons discarded Ferris as their weapon of destruction, but over the years they would meet again. Different women have taken on the mantle of Star Sapphire, and the female counterparts of the Guardians of the Universe also formed their own corps, driven by the power of love.
Krona's ambition and craving for knowledge led to the creation of the multiverse, when he created a machine to view the beginning of time. Upon doing this, his machine exploded and ended up destroying the universe, blowing it into infinite pieces that all became the multiverse. As his punishment, he was exiled by the Oans and left to live alone in the galaxy.
Hal Jordan worked with the original Green Lantern to defeat him, and at another point, he travelled to the Realm of the Dead to resurrect fallen Green Lanterns to defeat the deranged scientist. When he was killed by Jordan, his body was taken by the leader of the Red Lantern Corps, Atrocitus.
Nekron is the ruler of the Realm of the Dead - a place where the dead go before they pass on. He harnesses power from the souls of those that rest there for his own use, but like all villains, he became too greedy for his own good, wanting to feast on the spirits of those outside the realm.
In the Blackest Night event, Nekron was acknowledged as creator of the Black Power Rings, and also brought back to life various dead superheroes. Hal Jordan managed to defeat Nekron's tether to the real world - the Black Hand - but seeing those close to him reanimate in the way they did proved a more personal challenge than anything Jordan had seen before. In the New 52 version, Jordan defeats Nekron again, sending him back to the Realm of the Dead.
The color yellow has always been a weakness of the Green Lanterns, and it's revealed in Green Lantern: Rebirth that Parallax is the reason why the Green Power Ring has a weakness to the color. After Cyborg Superman and Mogul obliterated Coast City and killed the millions of civilians living there, Hal Jordan was left devastated.
Losing control as a result, he defeated the Green Lantern Corps, then killed Kilowog, Sinestro, and the Guardians. After Absorbing the power of the Central Power Battery, he emerged as the new Parallax. He was eventually stopped and found redemption, finally ridding himself of the ancient light of fear.
4 Hector Hammond
Once a petty criminal, Hector Hammond's transformation occured when he came across a crashed meteor. He used four scientists to study the meteor, and as they did, their intellect evolved at unimaginable speed. Jordan and Hammond came to blows, with the former saving the scientists and destroying all of their creations.
Hammond manages to give himself 100,000 years of knowledge, as well as granting him psionic abilities and immortality. He captures the Green Lantern, but is left unable to move or speak. He's also been a member of the Secret Society of Super Villains and attempted to romance Carol Ferris.
When the Manhunters murdered Atrocitus' wife and children, he became consumed with rage. He created the first Red Power Ring and became the Red Lantern after using the blood of the Five Inversions he'd killed. He searched for others blinded by hatred to form the Red Lantern Corps, including former Green Lantern, Laira.
The Red Lanterns and Atrocitus have been a deadly enemy to Hal Jordan, even turning him into a Red Lantern after the death of Laira, but thanks to Saint Walker he was returned to normal. Atrocitus' craving for blood and rage has often proved a tough match for Jordan's Green Lantern.
2 Black Hand
William Hand is one of Hal Jordan's oldest enemies, and has seen a massive change from mortuary worker to murderous villain. He has used his Cosmic Diving Rod to absorb the power of the Green Lantern Ring and use it against Jordan many times, even using it to murder his own family.
During Green Lantern: Rebirth, his hand was turned to coal and crumbled to dust. Hand was found by Krolotean Gremlins, who reconstructed his hand to absorb life from any living being. He became a murderer, but was stopped by Jordan. During Blackest Knight, he killed himself and was brought back to life to become a member of the Black Lantern Corps.
Undoubtedly Hal Jordan's greatest enemy, Sinestro was once a Green Lantern himself, but due to his darker tendencies he was cast out by the Guardians. What makes Sinestro and Jordan's relationship so interesting is the fact that it's not about pure hatred - it's much more complicated than that.
It was Sinestro that trained up Hal Jordan in the beginning, and ever since, there's been an aspect of respect that has caused the two to see eye to eye at times. The Sinestro Corps have proved almost unbreakable to Jordan, and the two have been involved in countless wars, with Sinestro even becoming a Green Lantern once again. Whatever the story, you can be sure it will involve an epic fight between the two former friends.