Lord of Monsters in the apocalypse

In the blink of an eye, the entire world underwent a seismic shift, triggered by a heedless scientist's inadvertent creation of a portal leading to an alternate dimension. This rift heralded the arrival of formidable beings known as Mutants, who initially displayed an inclination towards peaceful exploration of Earth, with intentions to return to their home planet. However, an unfortunate turn of events saw some Mutants succumb to madness, instigating a devastating conflict with humanity. In their desperate bid to resist, the human race quickly discerned the futility of their weaponry against the formidable powers wielded by the Mutants. As the precipice of defeat loomed, a handful of benevolent Mutants, distanced from the upheaval, opted to bequeath their powers unto humankind, ultimately aiding them in prevailing against their adversaries. With the conflict concluded, the world transitioned into an era where one's Mutant ranking became the linchpin determining their identity and shaping their future. Amidst this transformed landscape stood a young man named Xiao Yang, a victim of the chaos that had laid waste to his world. He embarked on an enigmatic quest, which, upon its completion, granted him access to a system. This system presented him with peculiar tasks, instrumental in his ascent towards greater strength and proficiency. However, one fateful day, Xiao received a disconcerting notification:[WARNING: YOUR SOUL POINTS ARE DEPLETING] [TO REPLENISH POINTS, CONSUME A HUMAN SOUL] [-1 SOUL POINT PER HOUR UNTIL A SOUL IS CONSUMED]