This MC Is Kickass - Chapter 271

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

[Please transform.] [The penalty for disobedience is death.] I am saying this because I have been wronged. Help me!

Anger issues was never a problem for Rio, but how can he say that after he swiped away his system in anger when the crystallization began on earth.With portals popping up and monster storming out of them how can Rio be expected not get angry at his lack of a level up tool.Armed with just an axe, as the days go by, Rio has a rapidly building peeve against his never present system and the last virtue on his list is tolerance.“System”“......... ”“System”“...…..”“Grrrrr!! Grrrr!!”With loud menacing growls the wolf like creatures approached, but Rio was busy looking for what spot in the room had better connection and would let him access his system.“If you guys don't shut up, I'll kill you.”Normally, worlds undergoing crystallization should be struggling to get stronger and survive the brutal process but on earth it is different as they are rather focused on pleasing their brutal and unforgiving Tyrant

5 years after the world changed, the final boss appeared.