Blastaar is a member of a race called the Balurrians, based in the Negative Zone. He ruled them for years as a brutal leader until they finally rose up and overthrew him, then sealed him up within a containment suit and set him adrift. It was only when the inhuman Triton braved the Negative Zone to save an adrift Mister Fantastic that the Explosive Belt around Earth revived Blastaar and he followed the pair through their portal and into the Baxter Building. There he met up with and joined the Sandman in order to take over Earth, but the Fantastic Four, with the help of Crystal, beat him and used one of Reed's inventions to shut off his powers, allowing them to return him to the Negative Zone.
Since then, Blastaar has tried to return to Earth and conquer it, but has been repulsed many times by various super heroes; including the Fantastic Four and the Avengers. While adventuring in the Negative Zone, the Fantastic Four have since run into Blastaar again on many occasions. Blastaar has also regained the throne of Baluur for himself, and then begun a conquest of the Negative Zone, which has been primarily kept in check by the interference of Blastaar's hated enemy, Annihilus.
Recently Blastaar has been seen in the positive universe in the company of the Spaceknights of Galador. Together they secretly fought Annihilus and his insectoid soldiers, which were known as the Annihilation Wave. Blastaar and the Spaceknights joined Nova and the United Front on the Kree planet of Canticus Prime, where they were able to defeat the forces of Annihilus.
Blastaar later appeared on the Kree Homeworld of Hala, where he led a Kree battalion against the techno-organic invaders known as the Phalanx. Blastaar fought valiantly but was stomped into the planet by a giant size member of the Phalanx. His fate is unknown at this time.
