I think Shinobi Legends is just a title, referencing the characters of the game or Shinobi and the Legends that they form, though I imagine if the name was thought of in that fashion, it was more precisely referencing the Forest fight system. Due to the fact that building stacks would make you a Legend, as you had all this stuff that only one person had in the show, that and Rp became more acceptable only as of late in comparison to the Reset system. if i've got my history right.
Edit: Did you mean existential?