Genius Bonus: The plot is extremely similar to that of Lord Byron's poem Darkness, to the point where it seems unlikely to be a coincidence. The difference being, of course, that in the poem the darkness doesn't go away, and everyone dies.
Made even more worrying in this panel◊, where said girl is on a Missing Poster.
Ho Yay: Rose's Wizardfic is based off of Evangelion, with Baptist and Claudius replacing Shinji and Kaworu, the subtext is still there. Baptist even describes Claudius as beautiful and charismatic.
"He always weirded you out with his strange obsession with TORCHLIGHT CEREMONIAL YAOI FESTIVALS though, you had to turn down his invitation to join the lost boys when he invited you to be the HONORABLE UKE. Whatever that means."
Big time with Hades. He was disowned and branded a traitor by his father, and is constantly insulted for being weak and incompetent. Sylja and Rose (and to a lesser extent Terlock) and pretty much the only people who don't treat him like complete garbage. He may be one of the main villains, but it's hard not to feel sorry for him.
Les Yay: Kanaya and Rose are still close after the ordeal. When John has troubles with understanding Troll romance, Jade and John question what the relationship between the two is.
On Halloween, Roxy and Jane are seen holding hands and sharing cotton candy, referencing their Idiosyncratic Ship Naming.