Five fiends assembled to combat a Legion of superheroes in times of crisis.
The Fatal Five composed of Validus, Persuader, Tharok, Emerald Empress, and Mano were brought together by 30th century's Legion of Super-Heroes to handle a vicious Sun-Eater threatening Earth-One's solar system. Instead, they become the teen's arch foes.
Centuries earlier on Earth-Two, a seemingly terminally ill crime boss known as the Hand recruit Red Dragon, Professor Merlin, the Needle Big Caesar and Dummy to become his Five Fingers, with the goal of cementing his criminal infamy. Instead, they were easily defeated by Law's Legionnaires.
Aside from the Dummy of Earth-Two, who's counterpart operated on his own versus his own world's Vigilante, we'll now investigate the other individual members of each team...