Trying to look up Black Water Grandfather and this article popped up.
Interesting idea that what we saw in 1x11 wasn't 100% accurate and that the debris was trying to show Bryan the truth any what happened.
Check out our review of Debris Season 1 Episode 11 to see how far we're reaching to find meaning with all of this debris and how the charact
Oh wow! If this senario is the case I will be really happy with the twist. I thought the backstory was a tad bit hollow and I’m hoping there is more to it.Â
I posted this same comment on reddit but I will post it here since you are searching for some answers on Black Water Grandfather too.Â
I did some searching for native creation myths and I think I may have found something. I think that the end scene may be inspired by the Jicarilla Apache creation myth and a creator figure named "Black Hactcin" (perhaps this is our "Black Water Grandfather"). In these myths the cardinal directions and their colors are important symbols: east, black; south, blue; west, yellow; north, white (also described as verigated or glittering). I found a few of these myths mentioning Black Hactcin either planting seeds, or sending out rays of light, or building different colored ladders (In these creation myths humanity and all life lives in the dark below the earth). It looks like this show is using metal in place of this.Â
 In one of these myths Black Hactcin caused an eclipse because the shamans thought they could control the newly created Sun. There might be something credible here?Â
Here is the book that I read some of this from. I can provide more sources if you need. I am by no means an expert, I just went down a rabit hole. I can only take things at face value since I am an outsider looking in on Native culture and mythos.
https://quod.lib.umich.edu/cgi/t/text/text-idx?c=genpub;idno=AGY7794.0001.001
