Rokk and Sorban
Rokk and Sorban
Intergalactic gamblers from the planet Ventura who square off with Superman - and later Batman - at the gaming tables.
In a first encounter, the duo bet that they can force Superman to kill someone and force the Man of Tomorrow to improvise an elaborate ruse to best them (S No. 171, Aug 1964: "Superman's Sacrifice!"). Later, in an adventure with Batman, as he gambles for Batman's life and the Earth's fate, Superman bests the luckless duo in a game of skill and chance (WF No. 150, Aug 1964: "The Super-Gamble with Doom").
Much later, in a cruel gambit, Rokk and Sorban create duplicates of Jor-El and Lara, merely to wager whether Superman would kill them on finding his "parents" to be actually evil (Act No. 582, Aug 1986: "The Strange Re-Birth of Jor-El and Lara!").
Also, these unapologetic wagerers are responsible for the second race between Superman and the Flash (chronicled in The Flash No. 175, Dec 1967: "Race to the End of the Universe").