Marvel Comics' Civil War was a 2006 crossover event that pitted The Immortal Hulk.
During the midway point in Civil War II the newly introduced Inhuman character named Ulysses has a vision of the future where the Hulk going on a rampage and kills several Avengers. In order to stop this from happening Hawkeye takes proactive measures and actually kills Bruce Banner before anything can happen. This scene would branch out and lead to the publication of the still ongoing comic called The Immortal Hulk, written by Al Ewing and illustrated by Joe Bennett. What makes The Immortal Hulk so good is that it isn't your typical superhero story- it's a straight-up horror comic that takes place in a superhero universe. Immortal Hulk #1 begins with the Hulk's resurrection after his death in Civil War II, except this time, the Hulk is portrayed as a downright terrifying creature of the night who seeks vengeance on anybody that he views as "bad".
Bruce Banner and the Hulk have always had a Jekyll and Hyde influence, but The Immortal Hulk is the first Hulk comic to truly embrace the character's horror fiction roots. It's quickly established that the Hulk isn't just an angry monster anymore, he is an intelligent and ruthless force of nature whose godlike healing factor lets him transform into Lovecraftian monstrosities made of flesh and bone. While the first few issues of The Immortal Hulk are effective as stand-alone stories of the Hulk and his nighttime adventures, the comic doesn't hit it's stride until Ewing starts to connect the stories together and transform The Immortal Hulk into a multi-faceted narrative about the Hulk and his role in the Marvel Universe.
The Immortal Hulk could have simply retconned Bruce Banner's death in Civil War II and called it a day, but Ewing and Bennett went above and beyond instead. Repeated references are made throughout the comic to a cosmic entity called "The-One-Below-All" - a satanic counterpart to Marvel's top god The One Above All. The-One-Below-All is revealed to be the source of all Gamma energy in the Marvel Universe, and it's explained that it is trying to use Gamma energy to control the Hulk and other people with Gamma powers in order to free itself from "The Below Place," where it has remained trapped for all eternity. It plots to use the Hulk's immense power and rage and transform him into a puppet that will annihilate all of reality. To make another Lovecraft comparison, this would mean that one of the founding Avengers is actually an antichrist figure being stalked by an Outer god on par with Yog-Sothoth. Immortal Hulk #24 demonstrates how terrifying this is by showing a flash forward to the future where The-One-Above-All succeeds in devouring all life in the cosmos-leaving the universe itself dead and empty forever.
Civil War II was a mediocre follow-up to another event comic that tried (and failed) to shake up the Marvel universe the way the original Civil War did in 2006. When it was first released, the Hulk dying was merely a plot twist meant to shock the reader and didn't have bearing on the story overall. The Immortal Hulk saw this twist and turned Bruce Banner's death into a golden opportunity to reinvent the Hulk and introduce a fresh new element to Marvel's cosmos. In doing so, it has become a modern classic of comics and may be the definitive take on The Incredible Hulk for the modern era.
