Only in the closing days of this great war did the Celts unite against their common enemy under the leadership of king Vercingetorix, but it was too late.
We can glean from the clues K follows throughout the story that there is a decoy, and before the big revelation near the end we're meant to think that the decoy was a girl, and was dead.
Modern versions of the parade feature marching bands from high schools across the country, floats, Broadway performers, celebrities, advertisements, and of course Santa Claus bringing up the tail end of the festivities.