싱숑
So from what I read in this chap, I think that these double black filtered squares are somewhat like the essence of their story that serve as a guide to the "end" or some similar destination. From comparing what Kim Dokja received as his qualification of the end it seems that it is more of a clear indicator than dried up and death(presumably because dried up may only refer to the end of some certain things, and death is more so an indicator of the end of a life). While Kim Dokja's end is more of an indicator of a more expansive "story"(can't find the right words lol). Like since the world is based upon stories and Kim Dokja's end is based upon the final chapter of those stories then ot kinda indicates the end of all. It was indicated that only nebulaes receive such a clear indication of an end before and most of then indicates the destruction of worlds like Ragnarok or the Armageddon.