A shiny, metal, naked lady, The Engineer is the second “nigh-omnipotent” member of her team, nearly matching the Doctor’s versatility and having less of his weaknesses. Her predecessor was a member of “The Changers”, working for The High- he was killed when Henry Bendix dropped a viral bomb on the Changers’ base. In his dying moments, this Engineer sent all of his work to Angela Spica, herself a genius who admired superheroes. Finding said work, Angelica distilled a nano-technological solution into a liquid machine form and injected herself with it, becoming a metallic heroine who then joined the Authority. Apparently being somewhat distant from others, she struggled “to find the right balance” between machines and people. She entered into a relationship with Jack Hawksmoor.
Probably the biggest Authority character in “BattleBoarder” arguments was The Doctor– a guy whose power was “I have lots and lots of powers”. Warren Ellis introduced a “Doctor” very early in his StormWatch run, and established that they had been around since “the beginning of human thought”- their numbers included Jesus, Albert Einstein, and more. The first one encountered was a member of The Changers, a group of anti-heroes, and his powers were chaotic in nature- he was killed by a missile strike, and a new Doctor was promptly created- a failed billionaire who went crazy with psychological issues and became a drug addict. When he was gifted the powers, he refused them, but found himself growing more and more powerful, and he was recruited by the Authority. His powers were as vast as they were unpredictable, and his feet of clay constantely befell him.
He suffered a drug overdose as the Earth itself revolted against humanity, and a “Renegade Doctor” took his powers and nearly killed the entire Authority- only Jeroen’s sympathy for living things convinced him he’d been wrong, and the Renegade fell to his knees in guilt and was killed by Apollo. Despite his power, The Doctor was killed by a drug overdose administered by the “Spirit of Murder”, Rose Tattoo. A new Doctor, a Palestinian suicide bomber named Habib Ben Hassan, brokered peace in the Middle East. Ultimately, the character seemed more like a way for the writers to be flashy or revel in human misery- almost like an exaggeration of a Marvel character or someone Grant Morrison would create (his stuff always came with “poetic speech”), but he was ultimately written out in a fairly snide way, dying of a forced O.D.
Swift is a bit of an oddity- a member of the Authority who debuted in 1995, and was not created by Warren Ellis at all. I suppose he wanted to have at least ONE middling link to the original StormWatch book, justyfing it as a follow-up instead of just “I’ma kill EVERYTHING and just start my OWN book! With beer! And hookers!”. Swift is, like most SW members who debuted then, a “Seedling” who gained her powers from a passing comet. She ends up with bird-like wings, and later talons, when her powers are developed further. Initially a pacifist, she joins up with some old teammates on a new squad- The Authority- in order to fight for a better world “regardless of the cost”. She was brainwashed into being a obedient trophy wife as part of a conspiracy to destroy her team at some point, but when she overheard the “off-button” code to break the brainwashing, she literally ripped his head off.
Swift was drawn as very flat-chested early on, but bought breast implants in The Authority and frequently boasted about them, perhaps a gag at the bust sizes typical to comics of the time. A later retcon introduces a mysterious, fated-to-be-important egg in Tibet that’s rescued from Nazis by Jenny Sparks in 1943, and it’s believed this was the origin for Swift. By the end of the series, she becomes the new Doctor, replacing the previous one.
A concept that could only be created by Warren Ellis or Grant Morrison, Jenny Sparks is the “Spirit of the 20th Century”, the living embodiment of 1900-1999 or so. She was introduced way back in 1996, and led StormWatch Black, their black-ops division, then went on to lead The Authority when Ellis revamped the series. Born on Jan. 1st, 1990, she was orphaned in the Titanic disaster and left penniless by an enemy of her family (who took over their vast fortune). Depicted as a superficial hedonist, she is nonetheless possessing of a strong sense of morality (well, for someone who slaughters her enemies viciously, I mean). Ellis finally killed her off after twelve issues of The Authority , having her give her life on the final day of the century (okay, technically Jan. 1, 2000, which is a year earlier, but nobody likes a pedant), electrocuting an alien “God” who’d originally created the Earth, and was planning to wipe it clean. Her replacement, Jenny Quantum, was promptly born to become the Spirit of the 21st Century.
When Ellis left The Authority , Mark Millar added stuff like her interacting with many famous figures of the 20th Century, including Albert Einstein, Ernest Hemingway, Adolf Hitler (telling a failing artist to give it up and enter politics, as he had charisma and “a talent for speeches”), Jacques Cousteau, John Lennon, Princess Diana, and many others. The New 52 at DC reintroduces her as an Asian woman who still lives into the 21st Century, and is the “planetary defense system” created by aliens.