A director interview
In this interview video, Dark Souls II director Yui Tanimura discusses the core of the series, trying to innovate while staying true to what made the last game so successful from a design perspective, and challenges faced during development.
Toward the end, talk of the game's closed beta is brought up and with it, a snippet of footage showing messages, bloodstains, summons, and invasions. Notice the White Phantom's health bar on the left-hand side of the screen, which comes in addition to the one located over the player character's head? Nice. Very nice.