In the real Marvel universe (Earth #616), the Illuminati, an elite group of heroes comprised of Iron Man, Mr. Fantastic, Black Bolt, and Dr. Strange decided that the Hulk proved to be too great a threat for the world to endure. For the sake of the planet, they tricked the Hulk into a shuttle and launched him on a preprogrammed course for an uninhabited planet far from Earth with suitable atmosphere and sustenance. It would enable the Hulk to live in peace for the remainder of his natural life. Unfortunately the Hulk never arrived on this planet.
His thrashing of the ship threw it off course and he landed on Sakaar, a planet similar to Earth during the Roman times but with highly advanced technology. Sakaar is ruled by the corrupt Red King. The Hulk was captured and sold into slavery as a gladiator for the amusement of the Red King. Hulk survived the gladiator games with the help of other creatures who became his warbound brethren. He ultimately won over the Red King's highest-ranking bodyguard, Caiera the Oldstrong, who possessed an ancient power to draw strength from Sakaar. This made her almost equal to the Hulk in terms of raw power. Their combined efforts dethroned the Red King, ascending to power as the Green King and queen. Caiera informed Hulk that she was carrying his child.
At this point the ship that brought the Hulk to Sakaar mysteriously exploded, killing everyone (except the Hulk) in Crown City including Caiera and his unborn child.
The Hulk and his warbound (out of the city at the time of the explosion) returned to Earth for revenge against the Illuminati. These events are detailed in World War Hulk #1
Like in the Earth 616 reality, the Hulk's ship malfunctioned and began a self-destruct sequence. This universe diverges in that instead of throwing the ship into space, Hulk grabs Caiera and throws her away from the explosion, telling her to take her stone form. As the warp drive explodes, Caiera is safe in low orbit. When she returns to the planet, she lands in the lava pits. She is unharmed due to her Oldstrong powers. She is met by Hulk's warbound: Korg, Miek, Hiroim another Shadow Warrior, and a member of the Brood. They ask here where the Hulk is. Still in shock, she replies that he is gone.
Miek takes the news very hard, believing the Hulk to be invincible. He mistakes aftershocks for the return of the Hulk and blindly runs through the lava pits to find him. He is quickly consumed by a burst of flames. The rest of Hulk's warbound retreat to a safe distance. Caiera absorbs as much of the planet's energy as she can process and orders the warbound to find a ship - they're going to Earth.
When they arrive near Earth, they stop off on the moon, destroying a large segment of its surface (presumably Attilan). When they arrive in New York, Dr. Strange and Sentry are the first to intercept their ship. Caiera is standing on the bow of the ship with a battered Black Bolt on his knees. He is wearing an obedience disk, used on Sakaar to force the wearer to do as s/he is commanded. She commands him to speak. Tearfully he obliges. The sonic waves peel the flesh from Strange and the Sentry killing them instantly.
She then heads for the Baxter Building where Black Panther, Mr. Fantastic, Thing, Storm, Human Torch, and the Invisible Woman are unable to withstand the force of her attack. Iron Man appears and attempts to help, but is beheaded by the warrior queen.
The remaining Avengers She-Hulk, Iron Fist, Luke Cage, Spider-Woman, Ares, Doc Samson, Ms. Marvel, and our webbed pal attack Caiera but are defeated (not killed since they were not directly responsible for the Hulk's death).
Hiroim reminds her that the guilty have paid. Caiera doesn't care as she intends to destroy the world for what they've done. Hiroim reminds her that if she kills everyone, there will be no one to honor her husband. Caiera agrees, but promises to make them wish they were dead.
Twenty-one years later the Earth is still under the rule of Queen Caiera. All humans have an obedience disk attached and do as they are told. Caiera's son arrives to inform her that "it's done".
They walk outside to reveal an enormous statue of the Hulk in gladiatorial armor. A sword in one hand, the other is outstretched, palm upward. She quickly climbs up the status into the open palm and transforms into stone, merging with the status. Her last thought is that "she will never leave him".
Caiera is an updated version of Jarella. She was the ruler of a subatomic world of K'ai that was romantically linked with the Hulk for a time. As you can imagine, this did not last. Caiera is portrayed as a compatible mate for the Hulk, as evidenced by the fact she was able to conceive a child with him. This was shocking during the original Planet Hulk storyline, and plays a significant role in this alternate-Earth story.
In this reality she has proven to be even as powerful – perhaps more – than her late husband. If nothing else, she is more ruthless. In World War Hulk, the Hulk wanted them to suffer as he had. Caiera wanted them dead.
3 webs. This is a decent story, but it starts out on a simple premise and ends in an unsatisfying manner. Caiera's revenge was well executed (bad pun, sorry) but it stopped short and the story suffers as a result. Had there been a more interesting finale, it would have been rated higher.