- Actor Allusion: It's not the first time Nana Mizuki voices a ninja...
- Playing Against Type: The murderous Hotarubi is played by Miyuki Sawashiro, who usually voices Genki Girls and Moe types. Then again, Hotarubi acts like one if you don't mess with her beloved Yashamaru.
- Relationship Voice Actor: Sho Hayami voiced Tenzen Yakushiji, high official of the Iga and main antagonist, and Risa Hayamizu voiced Kagerou, a Kouga Kunoichi that Tenzen raped and tortured towards the end of the series. In Hellsing Ultimate, Sho Hayami plays Enrico Maxwell, head of the Iscariot organization, and Risa Hayamizu voiced Maxwell's childhood self.
- What could be just as odd: Mark Stoddard voiced Tenzen Yakushiji, high official of the Iga and main antagonist, and Stephanie Young voiced Kagerou, a Kouga Kunoichi that Tenzen raped and tortured towards the end of the series. In Soul Eater, Mark Stoddard voiced Mosquito, an agent for the terrorist group Arachnophobia, and Stephanie Young voiced Arachne Gorgon... the leader of Arachnophobia!
Trivia / Basilisk