MTL - Fast Wear: on the Correct Posture of Counterattack - Chapter 248 Apocalypse kindergarten special episode IV

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

Aric Valerian, the fourth prince of the Valerian Empire, bears many titles: The Forgotten Prince, The Whore’s Child, The King’s Bastard—names that have been spoken more than his own. Born with a crippling illness and devoid of mana or ki, Aric was a disgrace, scorned by his family and the court. But when the gods cured him and gifted him the strength to fight, Aric dared to hope. He sought glory in battle, only to be betrayed by his brother and sent to die in a hopeless war. In his final moments, as death closed in, a mysterious text appeared before him… [Would you like to change your fate?] After being given another chance, Aric embarks on a ruthless journey to claim absolute sovereignty. [Ki Circulation Mastered: Strength +10] [System Upgrade: Advanced tactical planning unlocked] [Hidden Fortress Established: Stronghold security +15%] The forgotten prince claws his way through the treacherous landscape of imperial politics, he is forced to make impossible choices, each decision pushing him further down a path soaked in blood. He learns that true power demands sacrifice, and the price of vengeance may be his soul.

16 years old-- most boys would be falling in love, as their hormones all rise to unprecedented levels. Most boys at Riley's age would have dreams; dreams that will slowly grow into passion. Riley, however, at age 16... killed the world's number 1 superhero.

The apocalypse arrived, and Irving was betrayed and killed by his own girlfriend.After his rebirth, he was chosen by the Will of the Blue Star to be an internal beta tester of the Shelter Game, starting with a [Tenfold Drop Rate] and becoming a [Necromancer]!Ferocious and brutal exotic beasts are all tamed by him, gradually forming a powerful “Exotic Beast Legion” under his command!Building sanctuaries, hoarding supplies, upgrading outer walls, setting traps...Constructing the most powerful fortress in the apocalypse!“Since I have been given a second life, I will trample those who've betrayed me once under my feet!”...When the Dark Lord descended, Irving's shelter had become the strongest on the Blue Star!“You evil creatures, dare to covet Blue Star?”“Come on! Let me show you what true despair is...”“Remember, from now on, Blue Star is under my protection! Got it?”