I just had a pretty rad dream. Sorry if this post is a little messy, I tried to type it up as soon as I could in order to forget as little as possible.
It was based around a mechanic were multiple people could have the same vision/dream on purpose (I think it was because of supernatural powers that only a few people had) and have full control over their actions within that vision. And then there were these NPCs in the vision world whose purpose was to prevent people from having these visions for too long by attacking them. It was also possible to enter visions within visions, but it was a little dangerous, because then if the NPCs were coming for you, they could slowly blend into the vision within a vision and it would take you a while before you realized that they are NPCs in actuality and then there was very little time to wake up from that vision and start running in the other vision. However, it was possible to trick the NPCs if you managed to do something nonsensical enough that you would appear as though you were actually a part of that vision and not the person experiencing it, but it was difficult because overdoing it made it immediately obvious to the NPCs that you were just faking it. When you successfully managed to trick the NPCs, there would be a glitch in the vision which resets everything and turns the vision into something entirely different.
The first levels of visions were just more absurd versions of our current reality (but they did symbolically represent the stuff you would see at the deeper levels, but you could only understand that after you had seen the actual events). But the deeper you got, the more interesting they got; we could enter into visions to witness events that really happened in the past (well, at least until the NPCs started to blend into them and ruin everything — they would become characters like Gandalf and then you had to realize that Gandalf didn't really exist to tell that it's actually an NPC and you're being attacked in the previous level of visions). Then we used this to unveil the dark secrets of the Savonlinna Cathedral which actually had a hidden dungeon thing where lots of people were getting tortured and killed. We believed that those people were being targeted on purpose because they knew something that the church wanted to keep hidden, and we also intended to find out what it was that they knew (unfortunately, my dream ended before this could happen). The killed people were definitely a part of some sort of secret order, because they had a secret song (which was the Halo theme) that they sang to identify each other. The ones we managed to investigate further had also very tragic pasts in general, not just because of the church. We think the knowledge was also religious in nature. We also actually managed to correctly identify the song as the Halo theme in the dream, and I think we would have also looked into that later, but we didn't get that far either.
We had a team of 7 people consisting of me, Tsumugi Kotobuki from K-On, Wild Flower from Jade Empire, the bassist from my band, my childhood friend, a guy that I didn't know (who, in retrospect, was exactly like one of my online friends) and a girl I didn't know (I still don't think I know anyone who resembles her). The others had been doing it for a longer time, I just joined the group that day. The guy that I didn't know was clearly the most experienced person. Wild Flower especially had a strong connection to the Halo theme, and sometimes she had to enter some visions without the rest of us because she was the only one who could do it. Luckily, she also had the ability to describe what's going on in her vision to us that weren't in the vision. My childhood friend and the girl I didn't know turned out to be lesbians at one point, and they were harshly criticized for that by a random older woman who saw them kissing, and then I felt bad about myself because I couldn't defend them in that situation, but I did encourage them to be the people they really are as much as I could after the fact since they looked like they were troubled by it.
