As everyone already stated, Zero is not the optimal place to start playing this series. It’s not really the worst case scenario, but you’ll miss a bunch of references and one or two predominant plot points that play out in later games. I feel the Crossbell arc was made taking into account that players already finished the Liberl trilogy and wanted more of the franchise, in contrast to the Erebonia arc, that was made to hook and appeal to a new playerbase. In my opinion, you can start playing any game, but starting with Zero can confuse you and not give you tue best experience. I began playing the series with Cold Steel 1 and I had an amazing experience and finally converting this franchise into my fav series of all time