grammar (duplicate 'that')
In manga-based anime such as Naruto, fillers have been used to put distance between the anime and its source material, preventing an overlap which would cause trouble for both forms of the series. Filler episodes may follow a formulaic (and often predictable) plot, loosely based on a main episode, which will either enter the backstory of a certain aspect of a show (such as Rainbow Crystal saga of Sailor Moon's first season) or tell a completely new tale involving the main or supporting and even one-shot characters from previous episodes (The Garlic Jr. saga of Dragonball Z revisits the events that happened in its movie ''Deadzone''). Fillers also may introduce
that aspects that may complement or contradict the canon of the original source. It is not uncommon that whole story arcs comprised with filler episodes will be used within a series in order to fill an episode count and subsquently build up to a main story arc.