Adaptation Displacement: The fact Canaan isn't an anime original is pretty much unknown to most. This is because the original game was a Japanese only title until 2018.
Sugoi Sugoi: Either just Maria as her Catchphrase, or the show on a whole.
Mino-Sama: By those who like Mino.
HIGH TENSION!: the badass taxi driver after his apparent Catchphrase.
Some fans call him "Taxi Driver George" due to his awesomeness multiplied by a few times thanks to Joji Nakata voicing him, who's also known as George.
Alphard is the name of a star in the middle of the Hydra constellation. It is also known as the "Heart of the Snake" because of that (thus, no wonder Alphard commands the "Snakes"). "Al-Phard" also means "the lonely one" in Arabic because it's the brightest star in the whole sky sector.
Canaan is the name of the land that eventually became Israel in the Old Testament.
Before even that, "Canaan" referred to Phoenicians (you can even hear the phonetic similarity) in their own language. Phoenicians were the supreme mariners and traders of their time and founded Carthage, The Rival and Worthy Opponent to Ancient Rome. They also helped invent the modern European alphabets.
Hilarious in Hindsight: In first episode, on a tv screen the TVB Jade watermark is displayed on the further top-right. In spring 2013, the watermark was moved there in Real Life as part of the switch away from standard definition.
Moral Event Horizon: Liang Qi crosses this when she throws Hyakko through the Despair Event Horizon via tricking her into killing her savior and love Santana, and then mocking Hyakko's grief gleefully.
Liang Qi's death scene. Not only the musical backdrop add the tension of the scene, but the overall circumstance of the scene makes this feel like scene with a Shakespearean villain. Dying from an ironic, but in character means and a tragic story behind it all.
The most well-known fight scene is the one where Alphard and Canaan fight while Alphard is all dressed up.
Squick: Hakko becomes very intimate with Santana's dead body. Not just squick, but due to the circumstances, a brutal Tear Jerker since it shows you how far past the Despair Event Horizon the poor girl is.
Tear Jerker: Hakko and Santana's deaths. There's also Liang Qi's death, as horrifying as it is saddening.
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