The eldest among the Test Tube Babies, Cain is frequently perceived as Abel's elder twin. Once a kind and admired leader of the Mars Colonization Project, his life took a tragic turn after an accident claimed his life. Seth revived him by injecting Crusnik nanomachines, but this intervention also drove him to madness. In the conflict following the colonists' return to Earth, Cain and Abel sided with the vampire returnees. When Lilith's influence caused Abel to doubt their choices, Cain murdered her. Enraged, Abel and Seth confronted their brother, ultimately casting Cain out of the spaceship into the atmosphere, reducing his body to ashes. Remarkably, Cain managed to regenerate from the ashes, though he sometimes struggles to maintain his makeshift form.
Nine centuries later, Cain encountered Isaak Fernand von Kämpfer. Together, they seized control of the Rosenkreuz Orden, a minor Berlin-based organization opposed to the Vatican. Through Cain and Isaak's charisma and power, the Orden evolved into a formidable global terrorist entity. Cain's motivations remain obscure, yet he appears determined to annihilate humanity and the world. His followers address him as "Mein Herr," German for "My Lord," or "Mein Herr Contra Mundi," meaning "My Lord Against the World." He is most commonly known as Contra Mundi.
Upon learning of Cain's survival, Abel's primary objective becomes eliminating Cain once and for all. During Cain's assault on Albion leading the Rosenkreuz Orden, the brothers clashed for the first time, with Cain swiftly defeating Abel due to his superior Crusnik fusion level and Esther's unexpected appearance, which distracted Abel. Realizing Abel had sabotaged the rocket's control panels, Cain plans to merge with Abel's body to extract the access codes from Abel's memory. However, Abel is resurrected using Lilith's nanomachines thanks to Caterina and Tres, elevating him to Cain's power level. Their subsequent confrontation ends in a stalemate. With Ion Fortuna by his side, Abel vows to pursue Cain indefinitely until he is vanquished.
When Cain activates his Crusnik powers, his lips and eyes turn red, blue claws sprout from his hands, four white wings emerge, and a black lance materializes in his grasp. In this state, he can unleash devastating red energy. Even without Crusnik activation, Cain possesses the ability to project destructive, invisible force from his hands and exhibits superhuman strength. Among the four Crusniks, Cain alone has achieved 100% fusion with his nanomachines in the novels; however, in the anime, Abel also attains 100% fusion after receiving Lilith's nanomachines, avoiding insanity.
