It’s the last hurrah for the Ghost crew and they decided to go out with a proverbial bang. That is, they completely shot up whatever little semblance of cohesion and story the original series had in the first place.
And as I wrote in my Season Wrap-up of Kamen Rider Ghost, the season was directionless and a mish-mash of (many times) unconnected plot points. It was an even bigger disappointment and waste of potential than its predecessor Drive.
But Kamen Rider Ghost RE:BIRTH: Kamen Rider Specter, the V-Cinema and final official release for the season, just takes the confusion and insanity up a notch and maybe to the highest level too.