In Another World As Luffy!(Dropped)

Guy dies gets a note from a R.O.B responsible for his untimely demise, starts a journey in another world, maybe others later on. I'm not putting to much effort into this synopsis. All worlds mc will travel to will be original please give me ideas for original worlds if you can, or want to. Don't ask if this is a harem, I'll add one if I feel like it. Also this fic will get super dark at times so if your not into stories like 'Beserk' that hows it's going to be but slightly less dark. Also it's an original world I made on top of my head, it has no anime or manga. Cover by almy-art