The Black Watch: Rebirth in Wasteland

In a world shrouded by an implacable gray sky, where the sun's struggle to pierce through the bleakness manifests as a metaphor for the inhabitants' despair, a bleak tableau of chilling cold and stony darkness unfolds. This dystopian landscape is broken only by the relentless thunder of gunfire and the searing dance of flames. Amid this pandemonium, a monstrous creature, a sheep-headed behemoth glowing like molten lava beneath its craggy, dark-red skin, scales the razor edges of obsidian mountains, casting an imposing shadow on the embattled land beneath.
The formidable abyss demon is confronted by mechanized warriors, their weapons discharging in a ceaseless display of defiance. Amidst the ensuing chaos, a distinctive squadron known as the Thunder Group, identified by their uniquely engineered ostrich-like mechs, rally to challenge the monster's devastating onslaught.  However, their high spirits are swiftly dismantled by the demon's ferocity, reducing the battlefield to a grim relic of their failed resistance.
From a hidden refuge behind a fractured obsidian, two soldiers - a rotund rocket launcher-wielder and a captain donning silver-starred epaulettes - await their orders. The echoing command to charge leaves them steeling themselves against the overwhelming monstrosity blotting out the sky.  Their fate seems sealed as the colossal figure descends upon them.
In this world where time is a vague entity, oscillating between the cacophony of gunfire and the hush of silence, a young man named Chen Xing awakens within the confines of a crumbling bunker. He is a transmigrator, a wanderer from Earth who journeyed to this parallel, near-future reality 15 years prior.
Chen Xing is haunted by memories of his devastating confrontation with the abyss demon, the looming palm that darkened the sky, and the ensuing unconsciousness. Yet, his surprising reincarnation leaves him questioning the potential cycle of death and rebirth.  Armed with a multifunctional watch that indicates his life status, psychic level, and protection level, he stands at the precipice of a new life.
Once an Earthling and later a mercenary captain, Chen Xing is granted another chance to exist.  He was reborn 15 years after his second life！
Amid the savagery of this harsh world, survival becomes his ultimate victory. Yet, equipped with his newfound clarity of choice, he is determined to navigate the relentless challenges of this ruthless reality, yearning for a life not merely survived but truly lived.
But can Chen Xing really defy the odds, find a way to endure, and possibly even thrive in this perilous world?