For the last few months, Ubisoft and BNP Paribas have been exchanging visual swordplay in a post-it note video-game character war between their two buildings. Beginning with a single space invader on a Ubisoft window, the battle grew to epic proportions and captured the imaginations of people around the globe. On Friday afternoon, Ubisoft unleashed a three-story assassin from the game Assassin’s Creed. Some call it a swift strike to end the game, but will BNP counterstrike?