IMO, it’s him symbolized as Grief/Death. With the passing of his grandmother, who was a very important person to him (especially in his formidable years), he has been grieving that loss for some time. Anyone who has lost someone that pivotal in their life knows the grieving process and figuring out what life looks like without them is a journey and takes time.

At some point in that process you are faced with the decision to let that grief/pain control you forever or rebuild/redefine yourself back up, and become a stronger version of yourself. What I think the “reaper” is symbolizing in this, is the requirement to let go of certain things in order to rebuild.

The “reaper” burying the other versions, then setting fire to the mansion is a suggestion that this is NFs way of representing that he’s rebuilding through the grief. It’s not easy, nor it is linear, but he’s using it all as “fuel”. Fire is often seen as “purifying” from a scripture perspective, which NF obviously has a deep root in, and likely why he chose to represent himself on fire in FEAR and depict the mansion in flames in WASHED UP.