Teen Titans (Wolfman/Perez-era)
Nightwing/Dick Grayson, 'apprentice' to a heroic vigilante, he betrays his mentor and uses his skills for assassination, being more of a Red X / 'Slade's Apprentice' sort of character than any version of Robin. He's generally agreed to be one of the most dangerous un-enhanced humans on the planet, which has drawn the attention of the violent Starfire.
Starfire, half-Tamaranean/half-Okaraan 'warlord,' one of one hundred and seventy two members of the 'royal family' in ruthless control of the Vegan system, all competing to outdo (and /or kill) their siblings. She has come to the backwater of Earth, intending to conquer this world with the help of recruited local superhumans and mercenaries (since, like all of the royals of her system, she can't possibly trust any of her own people, who could be agents of her siblings!), to gain status back home by delivering a new world of slaves to her ruling grandparents.
Kid Flash, derived his speed powers by killing and drinking the chemically-saturated blood of his mentor, Barry Allen. A high speed vandal and thrill-killer, he seeks out other speed-empowered folk (such as his world's versions of Max Mercury or Jenny Quick) to drain their power as well, to both perpetuate and enhance his own. He likes to steal fantastic works of art and destroy them as 'gifts' to his lady, Raven.
Raven, red furred antlered hooved and with four golden eyes, Raven is very much Trigon's Daughter, sent to Earth to prepare it for his imminent arrival. But she's not really as much 'Daddy's Girl' as he thought, and she's dragging her hooves, enjoying her time away from her father, and working out a plan by which she allows more of his power into this dimension (which she will absorb), but then 'ruling it in his name,' rather than actually allowing him into this dimension to claim it himself... A dangerous game, to betray her father, but one she's up for. She plays other dangerous games, such as using her empathic abilities to toy with the affections of Kid Flash.
Cyborg, hitting up his researcher parents for some performance-enhancing drugs, this athlete was partially devoured by a shapeless extra-dimensional creature that evolved from a single earth bacterium left behind in an extradimensional pocket realm overnight (once the connection between earth and this parallel universe was severed, a single night on earth was a million years for the micro-organisms left behind in 'altered space'!). His father stole other researchers new impact-absorbing sound-generating metal to build a cyborg exoskeleton to replace the legs, arm and part of skull and torso devoured by the entity, turning his son into the ruthless dehumanized Cyborg.
Changeling, what remained of the organism that crippled Victor Stone (and completely devoured his mother) was thought dead when Victor's dad shut the dimensional portal down, ripping it in half between dimensions. What remained in this universe crawled away, retaining the DNA of those it had consumed, and took the form of Elinore Stone, visiting 'her' son during his convalescence. The entity now travels with Cyborg, having taken another human form (presumably by absorbing and devouring a young kid...), and having the ability to transform itself into any of the dozens of creatures that it has 'sampled' in it's time in this dimension. It's relationship with Victor, who knows it isn't his mother, but is actually the creature that killed her, is complicated...
Their primary foes include Slade Wilson, a mercenary adventurer with enhanced fighting abilities who considers taking out this superhuman villains to be 'the most dangerous game' and the only thing worthy of his attention, and the earth-manipulator Terra Markov, infiltrating their ruthless team as an undercover mole for the Terminator. Also Dr. Light and his Fearsome Five (young metahumans he's rescued from the Titans or their criminal allies), and Brother Blood (by no means a hero, Blood was high priest of Trigon on Earth until Raven arrived, and has figured out that she's stalling the grand invocation, attempting to keep Trigon *off* of Earth as she attempts to usurp it's mystical power for herself!).