Board Thread:General Discussion/@comment-6302057-20160307065615/@comment-1916997-20160314143120

NickM98 wrote: Based on the promo for "Devil's Due", I believe that the green river is the Styx. In the Disney film Hercules, Meg's soul ends up in the Pit of Death (formed from the Styx). In the promo, Hook is being lowered into a body of water that appears to resemble the Pit of Death. Hence the green river is likely the Styx. Now that's two rivers that we have identified by colour in the Underworld.

And CoolDudeAl, I think you're right. I think that the "worse place" is Tartarus, and Olympus is basically taking the place of the Elysian Fields. And the good news is Adam and Eddy said in a hot seat we will learn about the rivers and where they go, so they will probably get identified by name (or at the very least by attribute, i.e. "River of Pain", etc.), so we should be able to figure out which river is which.