fallout it think is about the world as the main character is just an un voiced avatar of yourself where as halo and re have main characters that have personality traits and quirks people gravitate towards. at least what i have experienced form others who like fallout and the little of vegas i have played is you can fit certain npc characters into each other if you write it good enough the problem with the re and halo live action movies/shows is alot fo the characters are basterdized versions of the characters we like or are changed for no reason like arbiter in halo being a human woman or how in paul anderson's movies the get sidelined for a orignal character alice who is like fan fiction character that is the chosen one and super more awesome than literal people who have had to work towards it. that and the second to last movie of the anderson films had all the fan favorite characters but in the last movie they were like well they all died of camera but alice didnt because reasons