DxD: Building A Demon Clan From Scratch. - Chapter 200: I’ll Rescue You

“On that day, Zach Harper died-” Or at least that was how it was supposed to be. I died. But there was good news, and bad news. The good news; I was reincarnated! Transmigrated into the World of Aethoria! Holy fuck, miracles do happen! But the bad news was, “Huh? What’s this?” ... [DING!] A New Quest has been issued:- Type:- SURVIVAL Name:- Quest To Becoming Stronger: Description: The {Great Calamity} is coming...Get stronger and survive. Duration-: ... Reward:- ... Penalty:- Death, ??? ] ... I had to survive.

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

Ye Fan accidentally obtained a billion crystal technology system, and since then, he has become out of control.

Android: You do n’t even have a mobile phone system. I want to make it impossible for you all!
Ye Fan: Sorry, I researched it out, it seems to be more powerful than yours!
BMW Benz: Our engines are famous all over the world!
Ye Fan: Sorry, I do n’t have an engine, I only have magnetic levitation, and the speed is only a few times that of yours. Do n’t worry, take your time!
…
Enemy: Is he still human?
Who can stop this!

- Description from Qidian

Ethan transmigrated from earth to a post apocalyptic martial world with a system.His system has only one function: Double the attribute every day. Watch him rising in the universe with a pace faster than the speed of light.