A System appears from the start.
On the first day, my sign-in reward is a cell editor.
It lets me perfectly develop and control every cell in my body, and edit them as I please.
Modify my skin cells, and my skin becomes as hard as diamond, impervious to blades and bullets.
Modify my white blood cells and macrophages, and sickness becomes a thing of the past.
Modify my brain cells so they never deteriorate, and activate every one of them. A photographic memory? That's just the basics.
Modify my cells so they can produce nuclear reactions directly inside themselves, converting matter into energy. Every cell is basically a nuclear reactor.
On the second day, my sign-in reward is an advanced martial arts technique: Tai Chi. In this era, ancient martial arts have been lost for hundreds of years, but they make their return on this very day.
On the third day, my sign-in reward is a supreme body on par with the Ancient Sacred Body.
On the fourth day, I sign in and get...
I am a walking supercomputer, a walking war machine.
In an era ruled by superpowered individuals and mecha pilots, I can still reign supreme.