Golden Age
The original hero to use the name the Blue Beetle was Dan Garrett, who was an archeologist. One day while working on a dig in Egypt, he discovered a strange blue Scarab totem of unknown age and origin. The Scarab, later revealed to belong to the Pharaoh Kha-Ef-Re, granted Garrett incredible powers, which he used to escape a cave-in inside the tomb. Dan used these new powers to battle evil as one of America's "Mystery Men," the Blue Beetle, during the Golden Age of the 1940s. The scarab gave Garrett super strength, invulnerability, flight, the ability to project energy bolts from both his hands, and other enhanced senses.
After years of costumed adventuring, Garrett became a professor of archaeology at a local university. One of his students was a young Ted Kord, who even in college was exhibiting signs that he was a technical genius. The pair formed a bond, and when Ted discovered his uncle Jarvis was in fact a criminal, he turned to Garrett for help in defeating him. Together, Dan and Ted were able to stop Jarvis Kord, but Dan Garrett died in the process. As he lay dying, Garrett asked Ted Kord to continue the Blue Beetle legacy, and passed the Scarab down to him.
Silver Age
Ted Kord kept his vow to become the next Blue Beetle, but he soon discovered that the Scarab did not work for him. Nevertheless, Ted trained himself to become an expert fighter, and a got into prime physical shape. He also used his scientific genius to create a variety of crime fighting gadgets, and also made himself an advanced flying vehicle shaped like a large beetle, which he nicknamed "the Bug." Fashioning his own Blue Beetle costume, he soon established his own identity as a Super-Hero, and even without powers, came to eventually equal Dan Garrett. Operating out of Chicago, Ted took over his father's company, Kord Omniversal, and under his guidance, it became one of the top tech companies in the world.
Post Crisis
After the events of the 1984-1985's CRISIS ON INFINITE EARTHS, Ted let his father take over the company again, so he could focus on being a Super-Hero. He joined the newly formed Justice League International, where he quickly became best friends with his teammate Booster Gold. The two men had quirky senses of humor, and both were millionaires who had fallen on hard times. In addition, both heroes were not taken entirely seriously by the Super-Hero community at large, giving them something else to bond over. Together, this duo was given the nickname "Blue and Gold," and served on the League for many years, under the guidance of billionaire Maxwell Lord.
When both heroes both received devastating injuries fighting the monster known as Doomsday, it signaled the beginning of the end of their time in the League. Blue Beetle would continue adventuring, but soon Ted took back control his company from his father, and soon he made Kord Industries a subsidiary of Wayne Enterprises. Entering into semi-retirement from his Blue Beetle persona, he still helped the team called the Birds of Prey, not only with funding, but also supplying them with technology. It was during his time helping out the Birds that he discovered that he had a heart condition, meaning he had to seriously limit the amount of costumed adventuring he could do. Still, he managed to go on adventure with L.A.W., the Living Assault Weapons.
One of Ted Kord's final acts was his discovery of a conspiracy that had grave implications for the future of the heroic community. Sifting through various clues that almost all of his former Justice League comrades ignored, he discovered that the Justice League International's former leader, industrialist Maxwell Lord, was behind a plot to catalog every Super-Hero's powers. This was all in an effort to control them, or ultimately eliminate them. When Ted confronted his old friend, he admitted he was behind the plot, but also offered him the chance to join him. When Ted categorically refused, he shot him in the head, killing him.
Sometime later, his best friend Booster tried time travel to save Ted. But in erasing the timeline where he died, it began a butterfly effect that led to a terrible future. Realizing he was meant to die, Booster allowed Ted to return to the moment where Max shot him, and die as he was meant to. His body was later resurrected to become a member of the Black Lantern Corps during the BLACKEST NIGHT.
Post Infinite Crisis
Although Ted Kord had Dan Garrett's scarab, it never worked for him. He gave the Scarab to the wizard Shazam, who kept it in the Rock of Eternity. When the Rock was destroyed in the events of the Infinite Crisis, the scarab was sent to Earth, where it landed in El Paso, Texas. A Mexican-American teenager named Jaime Reyes found the Scarab in an old lot, while on the way home from school. Taking it home, that very night, the Scarab was activated, and grafted itself to the base of Jaime's spine.
The Scarab gave Jaime a suit of armor that encased his body, giving him powers like enhanced strength. The armor also had technomorphy, which allowed it to form weapons, energy shields, an energy cannon, and can form other weapons like swords. The armor allows him to fly as well. On occasion, the armor takes over from Jaime, and he has to wrestle control back from the Scarab.
After helping Earth's heroes during the Infinite Crisis, Jaime became the local hero of El Paso, and often came into conflict with his hometown's reigning crime boss, La Dama. During this time, he also joined the Teen Titans, and even accepted a chance to work with Ted Kord's best friend Booster Gold as part of the Justice League.
Jaime learned the truth about the Scarab, when he found out the Reach, a distant alien civilization of interstellar conquerors, had created the Scarab and left it on Earth. At first, the Scarab had been programmed to obey the Reach, and be in instrument of their collective will. It was also meant to take control of its host, establishing whoever wore the armor as Earth's defender, and then using the host to help them exert control over the entire planet. But over the course of the centuries the Scarab had spent on Earth, it had been infused with magic, a corruption which prohibited the Reach from fully controlling it. Now bonded with Jaime, it began to resist the Reach's programming. The Scarab now gave itself a name, Khaji Da, and together it and Jaime were able to defend the Earth from an invasion from the Reach.
New 52
After the events of 2011's FLASHPOINT, reality was altered, and the events that led Jaime to receive the Scarab were changed. It was now Jaime's friend Paco who discovered the Scarab when he and his friends saw the Scarab floating in the water in El Paso. When Paco went to check it out, it shocked him, essentially rejecting him as a potential host. The Scarab then attached itself to Jaime forcing him to become its new host body.
Not understanding the Scarab, Jaime went to scientist and C.E.O. of Kord Industries, Ted Kord, for help. In the post Flashpoint reality, Ted had never been killed by Maxwell Lord, and instead just retired from heroics. Together the two learned of the Scarab's ties to the alien Reach. It was Ted who suggested that Jaime uses his new powers to help people, and ultimately, Jaime agreed. He then decided to succeed Ted as the new Blue Beetle, with Ted acting as his advisor and mentor, and occasionally, as tech support.