The Fuel Spirit (フューエルスピリット Fu~yūerusupiritto ) is the energy generated by human emotions and feelings. Through different special techniques, this energy can be harnessed and converted into magic energy. The greater or stronger the feelings, the more emotional energy is generated.
There are two variants of the manipulation of Fuel Spirit:
Noir Fuel Spirit
Noir Fuel Spirit (ノワールフューエルスピリット Nowārufu~yūerusupiritto ) is way to convert to magical energy by utilizing strong human emotions. Croix Meridies development artifacts and an app capable of absorbing the negative feelings to make it an energy source to turn into magical power, seeking to obtain a new source of magic before the decline of the magic in the world, as well as obtaining the energy necessary to break the seal of the Grand Triskellion. According to Croix's research, anger is the emotion that produces the most power.
Dream Fuel Spirit
Dream Fuel Spirit (ドリームフューエルスピリット Dorīmufu~yūerusupiritto ) is the way to turn dreaming power into magical power. However, those sucked for dreaming power are deprived of magical powers. In spite of this, the loss of magical powers as result of Dream Fuel Spirit is not permanent, as witches who lost their powers by this magic can regain it by reworking on their magic skills. Diana, who lost her magical powers as result of Dream Fuel Spirit magic managed to regain it through reworking on her magical skills from the beginning. Shiny Chariot used this power to turn the dreaming power of her show audience into magic, resulting in her viewers losing their possible magical abilities. This is what caused Akko to be unable to fly in the first place until she recovered it by the events in Tree of Leaves.
- The concept of Fuel Spirit was previously introduced in second short film. However, its depiction noticeably different due to anime's updated lore.