Translation - Brasiliaanse Portugees-Engels - A Essência da Nova Fábula do Cristal: A Saga da...

Although "Saga" would be a more faithful translation, "novel", "narrative", and just plain "story" could take its place depending on a larger context.

In "the Mythology", "the" can be omitted depending on how specific this "Mythology" is in the whole text. This would also render possible the use of "the Mythology Saga" as a phrase itself. (Note that the same thing may apply to "Crystal")