Talk:The Curse of Day/Part1/@comment-32712012-20170811002308/@comment-32712012-20170811035731

It's taken from a distinction in Sonic Adventure 2 and Shadow the Hedgehog, in which levels are divided between "Hero" and "Dark" (and, in Shadow the Hedgehog, "Neutral). Here, "H" stands for "Hero" and "D" stands for "Dark".