Marrow

There, Mikhail had established a citadel for himself on the top of a massive hill. The Social Darwinist philosophy of "survival of the fittest" was the only thing that governed society. If someone could reach the summit of the hill, they were considered "fit" and worthy of being part of Gene Nation.

The former Morlock leader Callisto cared for Marrow during this period and displayed a maternal attitude towards the young mutant. When her powers fully manifested, she was forced to "up the hill", becoming more savage and killing her opponents to survive. When she managed to reach the top, Mikhail considered her fit to join his elite fighting team, Gene Nation, which eventually became a terrorist group whose mission was to punish humans for their hatred towards mutants.