* CargoShip: Kai is jokingly shipped with his books as he spends all of his downtime reading and is seldom seen without a book in hand.

* EnsembleDarkhorse: This series has quite a few of them.

** Andre was originally created for a one-off appearance in the Phantom of the Opera animated music video. He became wildly popular from this to the point of becoming a [[BreakoutCharacter Breakout Character]], gaining an origin story as Kai's estranged half-brother and eventually appearing as a major antagonist in the series proper.
** Grey, a young male fox who appeared briefly in episode 6 as [[spoiler: a test subject in the hawks' dragon curse experiments]], became wildly popular after his introduction despite not having appeared in the series since. At one time, he even rivaled main characters such as Mark in popularity. Despite having minimal screen time in canon, fan art and writing have further developed his personality and interests to be a timid but kind kid who loves eating fruit and building forts. [[WordofGod This became]] [[AscendedFanon canon]] once the character's popularity soared.
** Yazzi and Jazzi, the two female foxes who appear in the Bumblebee music video, have their fans despite not having appeared in an actual episode yet.
** Tori, the keeper of the upside-down library, is fairly popular for her quirky personality despite not having appeared since her debut episode.
** The elderly human couple are beloved by some due to all of their brief appearances being humorous.

* EvilIsCool:

** Andre is one of the most popular characters in the series largely because of this. His dangerously eccentric personality only helps matters.
** While not quite as popular as Andre, King Garuda is liked for his intimidating presence, metal eye, and (in later episodes) deep voice.

* GrowingTheBeard: The art direction and tone of the series has evolved greatly over the years, which can be attributed to the creator's young age at the start of its creation, and thus her developed art, writing, editing, and production skills over time in the years since. While the entire series is beloved and nostalgic to those who followed it from the early days, the newer episodes have come a long way compared to where things started.

* IronWoobie: Kai can be seen as this. He has been through a lot, [[spoiler:having been trained by the Cooperates to withstand any physical trauma and later thrown in a near-abandoned prison for leaving the Cooperates and thus being deemed a traitor, to be made an example of and discourage other trainees from turning against the organization.]] Kai has learned to suppress his emotions and no longer outwardly seems to be fazed by much.

* SongAssociation: Early episodes feature the song Butterfly by eurodance group [[Music/SmileDK Smile.dk]] as the theme song. This combined with butterflies appearing as a symbol in-universe have created a strong association between the song and the show.

* StoicWoobie: Kai. See the [[IronWoobie Iron Woobie]] entry for details.

* SuperCouple: Kiki x Kai is widely loved by fans due to the clashing personalities between the two, and has received the most fan art and attention by far out of the implied ships among main characters.

* WhatDoYouMeanItsNotForLittleGirls: The series is pretty kid-friendly and contains a lot of imagery of fairy wings, butterflies, and rainbows. However, particularly in later episodes, it has developed into a fantasy epic with themes of assassination, violence, betrayal, and attempted murder.

* TheWoobie:

** Louie is very much this. [[spoiler: He was put through fusion experiments by the hawks at a young age and is cursed to transform into a dragon every time the moon is 3/4 full.]] It is also implied that [[spoiler: he may sometimes not be able to control his powers when the dragon side takes over, as shown in original art by Stickfreeks and in the Eden animatic]]. His youthful appearance and mannerisms shown in more recent episodes have only garnered more fan sympathy.

** It's hard not to feel sorry for Kai. He is implied to have [[spoiler: lost his family at an early age]], grew estranged from his half-brother who he was once close with, and [[spoiler: was put through intense physical and mental training to be virtually un-killable which affects him more than he lets on]].

** Grey's popularity is largely due to his woobie status despite only appearing briefly in one scene. Similar to Louie, he was [[spoiler: a test subject in the hawks' dragon experiments]] and is shown to be fearful and timid.