The Bad Guy from Both Worlds: I Am Picking up Rubbish in the Wasteland

[This book is not the Holy Mother, it kills decisively, please feel free to eat it] Thank you! A person squats on the toilet in a rental house and opens a portal to the wasteland in seconds! The left hand resells last-minute food and wildly collects source crystals to become a one-punch superman; the right hand colonizes the wasteland and becomes the overlord of another world!