Most DC characters end up by themselves or clustered into groups. Green Arrow might shoot his arrows on alone but he was a member of Batman’s backup JLA plan. Cyborg did his own thing most of the time but served with several incarnations of the Titans. Although heroes traditionally band together into groups such as the JLA or JSA, other heroes have legacies all their own.
Beginning all the way back in the days of WWII, Jay Garrick was the first in the Flash legacy. All the people to step into the red boots of the Flash are kind-hearted, brave and have at least a brief knowledge of chemistry. Sadly, most people to have taken the name have also ended up dead for a time. Most speedsters draw their powers from the semi-sentient Speed Force but not all. Superman, Velocity users and the Reverse-Flashes have powers originating from other sources. Although the Flash name began with Garrick, other speedsters predated him and the legacy extends to at least the 853rd century.
Serving as an intergalactic police force, the Green Lantern Corps began with one member per sector with the known universe divided into 3600 but quickly expanded to two with several other oddities – such as the Corpse and Starheart user Alan Scott – serving under the banner as well. The only prerequisite for joining is being able to overcome great fear – apocalyptic levels of fear. Following Hal Jordan’s selection, the Corps began facing greater and greater challenges. What they had been told is a necessary impurity that rendered them powerless against yellow was revealed to be Parallax, the embodiment of fear. The Anti-Matter universe began invasions and other foes also began attacking. With other Corps rising alongside them, the Green Lanterns remained resolute and one of the greatest forces in the DC universe.
With the Justice League #50 revealing that the Joker is not just one maniac but three across the ages, it makes for one twisted legacy. Pinpointing exactly where each one starts and ends is a difficult prospect at best but I’m fairly sure that the original Earth-2 Joker is the first, the second began showing up with Earth-1 Bruce Wayne being introduced in order to keep Batman young and the New 52 brought the current Joker into the picture. Regardless of which is which, each has used Joker Venom and an array of twisted gadgets and gags to terrify Gotham.
The immortal princess and queen of Themyscria, both Diana and Hippolyta took the name Wonder Woman when venturing into the world of men. Although the duo begin as separate and unique heroes, they can’t stop the people that feel obligated to take up their own mantles in turn. As royalty of a foreign nation, they don’t simply fight whatever villains come their ways but have to deal with the political field. When Diana killed Maxwell Lord, there was significant backlash against all the people who followed the Themscriayan ideals. Although Diana was cleared, it was a long struggle to regain the trust of the public.
Gotham’s Dark Knight, Bruce Wayne is – and will always be – the best Batman. But his dark legacy extends far beyond the streets of the grimy city he calls home. During the Battle for the Cowl arc, several potential Batmen come to the fore with Grayson finally emerging the victor. Although Bruce remains the only current Batman, we’ve seen several others in various times. Batman Beyond’s Terry McGinnis, Damian Wayne in a possible timeline as the Batman in a Jokerized Gotham. Even in the far-off future of the 853rd century, there’s a Batman serving with the Justice Legion Alpha.