History YMMV / KnightsOfSidonia

** Tsumugi's [[spoiler:tentacle. It may behave like a young girl, but it resembles nothing more then a massive penis]].

* DespairEventHorizon: [[spoiler:Kunato after Nagate saves Sidonia from the planetoid Gauna. In his mind, he is a failure because a lesser pilot saved the day and will be celebrated as a hero, and because his actions [[Main/MoralEventHorizon resulted in more pilots dying than civilians being saved]], he also regards himself as a murderer. When Tanikaze tells him that, while he'll never forgive him, he wants even Norio to be happy in Sidonia, Kunato cannot summon the courage to speak to him and instead runs back into his home and openly weeps]]. He's one of the very few characters in fiction to both cross the "forever evil" and "forever hopeless" event horizons.

* NightmareFuel: To prevent a Gauna from reaching Sidonia, Kobayashi is forced to order an emergency acceleration. The arificial gravity system become unable to compensate for the acceleration, causing the residential blocks to crumble and many to die falling to their deaths. The scene is all the more horrifying in the anime.

* LesYay: [[PairTheSpairs Izana and Yuhata]] have been getting an increasing number of moments with Nagate [[spoiler:and Tsumugi growing closer]].

* UglyCute: Tsumugi's tentacle-head-thing.

* DespairEventHorizon: [[spoiler:Kunato after Nagate saves Sidonia from the planetoid Gauna. In his mind, he is a failure because a lesser pilot saved the day and will be celebrated as a hero, and because his actions [[Main/MoralEventHorizon resulted in more pilots dying than civilians being saved]], he also regards himself as a murderer. When Tanikaze tells him that, while he'll never forgive him, he wants even Norio to be happy in Sidonia, Nagate cannot summon the courage to speak to him and instead runs back into his home and openly weeps.]] He's one of the very few characters in fiction to both cross the "forever evil" and "forever hopeless" event horizons.

** Tsumugi's [[spoiler:tentacle. It may behave like a young girl, but it resembles nothing more then a massive penis]]
* MoralEventHorizon: [[spoiler:Kunato purposely sabotaging a mission just so that Tanikaze looks incompetent for incredibly petty reasons is bad enough. But doing so gets Hoshijiro Shizuka killed and Honoka En placed in a coma. He never seems to feel any guilt over this. Having said that, his encounter with the Benisuzume leaves him quite visibly shaken]]

* DespairEventHorizon: [[spoiler:Kunato after Nagate saves Sidonia from the planetoid Gauna. In his mind, he is failure because a lesser pilot saved the day and will be celebrated as a hero, and because his actions [[Main/MoralEventHorizon resulted in more pilots dying than civilians being saved]], he also regards himself as a murderer. When Tanikaze tells him that, while he'll never forgive him, he wants even Norio to be happy in Sidonia, Nagate cannot summon the courage to speak to him and instead runs back into his home and openly weeps.]] He's one of the very few characters in fiction to both cross the "forever evil" and "forever hopeless" event horizons.

* SugarWiki/AwesomeMusic: The anime's opening, "Sidonia". Also an {{Earworm}}.

** On the other hand, it can be argued that the anime flows better than the early manga, as (with the benefit of hindsight) it tweaks the timeline so that e.g. Yuhata is introduced earlier and Kunato humanized a bit (without diminishing what an asshole he is).

* DieForOurShip: Hoshijiro.

* MoralEventHorizon: [[spoiler:Kunato purposely sabotaging a mission just so that Tanikaze looks incompetent for incredibly petty reasons is bad enough. But doing so gets Hoshijiro Shizuka killed and Honoka En placed in a coma. He never seems to feel any guilt over this.]]

* MoralEventHorizon: [[spoiler:Kunato purposely sabotaging a mission just so that Tanikaze looks incompetent for incredibly petty reasons is bad enough. But doing so gets Hoshijiro Shizuka killed and Honoka En placed in a coma. He never seems to feel any guilt over this.]]

* MoralEventHorizon: [[spoiler:Kunato purposely sabotaging a mission just so that Tanikaze looks incompetent for incredibly petty reasons is bad enough. But doing so gets Hoshijiro Shizuka and Honoka En killed in action. He never seems to feel any guilt over this.]]

* MoralEventHorizon: [[spoiler:Kunato purposely sabotaging a mission just so that Tanikaze looks incompetent for incredibly petty reasons is bad enough. But doing so gets Hoshijiru Shizuka and Honoka En killed in action. He never seems to feel any guilt over this.]]

** Tsumugi's [[spoiler:tentacle. It may behave like a young girl, but it resembles nothing more then a massive penis]]

** For the science fiction fans, there is alway an argument about whether the Gauna assimilate or digest their victims.

* AlasPoorVillain: [[spoiler:Kunato]] really didn't deserve [[spoiler:getting bodyjacked by Ochiai]]
** The Gauna [[spoiler:Humanoid placenta. It's outright stated that it remembers the human it is based on, including it's attraction to Tanikaze]].

** Tsumugi's [[spoiler:tentacle. It may behave like a young girl, but it resembles nothing more then a massive penis]]
* WhamLine: [[spoiler:[[{{Blame}} Graviton. Beam. Emitter]].]]

** Tsumugi's [[spoiler:tentacle. It may behave like a young girl, but it resembles nothing more then a massive penis]]