This is a dark Alternate History arc that follows what might happen if Mukuro had decided to make Xanxus his tool of conquest instead of Tsuna.

“I dunno,” Hizashi shrugged. “He’s clearly not the worst guy in the world, considering who he goes after.” “I heard he’s pretty brutal,” he pointed out, not disagreeing. “Some of those people deserved brutal,” he said and decided to push a little more. “Did you hear about his last victim? That pharmaceutical director using experimental drugs on his son?” “Daughter,” Shouta corrected mindlessly before stiffening. Hizashi grinned. Gotcha.