In Chapter 1038 we see Zoro wakes up and sees a hooded skeleton wielding a scythe ready to strike him while he himself can’t move at all.
I’ve seen a lot of ideas/theories about this scene and wanted to share my thoughts. Before the chapter pans to Zoro outside the skull dome, we get a page where Chopper finally recovers from the side effects of the drug he took to prolong his Monster Point. Then Chopper goes onto say that’s he’s more worried about Zoro than he was about himself and that “in exchange for a temporary burst of extreme healing he’ll have to suffer TWICE the damage later”.
I believe that the grim reaper is a manifestation of the after effects Zoro was warned of. I think the grim reaper is a hallucination and in reality it is the damage being inflicted on Zoro. This goes with his quote from Chapter 1036 about being the “King of Hell”, I think Oda is setting up another “nothing happened” moment for Zoro like in Thriller Bark.
Just like how Zoro took all of Luffy’s damage on top of his own, now he will have to take on twice the damage he’s already take with the after affect of the drug. Literally or figuratively going to hell and back to survive and becoming the King of Hell.
I think this is going to be a great spiritual scene of Zoro’s immense willpower which will serve as an evidence that he indeed does deserve to have the Supreme King’s Haki.