Canonically portrayed as a binary energy, The Force in Star Wars consists of a light and dark side that "binds the galaxy together" and stems from life itself. Through this dichotomy, as a consequence, Force-wielders are depicted as either Jedi or Sith -- religious practitioners whose two distinct monastic philosophies are at odds with one another. Due to their intrinsic natures, a constant power struggle within the galaxy ebbs and flows between both groups, depending on which is stronger. This dynamic, of course, was brought to fruition by Star Wars creator George Lucas, and he won't have it any other way, despite some of the fandom arguing that there's a middle ground a character can take between the two ideologies: becoming a gray Jedi. Nevertheless, according to Lucas, grey Jedi don't exist.
Source：https://www.cbr.com/anakin-skywalker-ahsoka-tano-grey-jedi-at-heart/
