Though considering the average Touhou Plot, "darkest" could just mean Reimu doesn't have tea at the final boss's place in the end.
Several of the manga and especially ZUN's music albums reveal that things in both Gensokyo as well as the outside world are much darker than they appear to be in the games.
ZUN only said it's darker than usual in his blog, not necessarily the darkest game.
What IS the darkest Touhou game, anyway…?
Probably Double Spoiler or LoLK. Still, I'm just expecting the same old presentation as other games, telling the story mostly via character interactions.
Probably Double Spoiler or LoLK. Still, I'm just expecting the same old presentation as other games, telling the story mostly via character interactions.
I'm going to try some guessing here. Know what creatures have some potential of appearing? Those guys.
They're beasts, and from hell. I remember learning about them through Shin Megami Tensei, and ZUN used to take some inspiration from that series for his early games. They could do good dual bosses (like Satono and Mai), but preferably just at Stage 3, guarding the entrance of hell.