This scene in the opening is brief but it looks like what I saw when someone told me to look at the egregore of Japan. It's a stone platform where people are practicing shinto and zen rituals while a lot of malevolent smiling faces are looking down on them. There is no hell or any dead bodies lying around, because anyone who fails to follow the ritual will be eaten by yokais.
Other countries for commparison: South Korea is a burning field with burning bodies. North Korea is a huge square with a government building and a statue of the great leader. People are sitting on the ground hacking stones, but they are not alone, they are with their families. There is no hell. France is just a ruin with a basement and down there are a few burning corpses. UK has a stone cottage with toxic mist above it, go past the mist and you can ascend. Go down from the cottage and there is a mud road with whores sitting alongside it, leading down to a burning city. USA was shown as a daoist temple built from human skeletons, but a Daoist deity appeared and said he was tired of it, then leveled it with the ground. The entire middle east is just Allah.
Looking at the ending scenes of the anime again these give a feeling of the fantasy worlds portrayed in arcade games from the 1980s, also released for home computers, like Altered Beast and the Nintendo 8-bit game Rygar. These are astral places, during one session we were lead to the place of Rygar.
