Interesting book from Katherine Isbister about social psychology principles that are applicable for game characters design.
A book about emotions in games from David Freeman. It’s old (2003), and some methodologies might look controversial, but I found this book interesting.
GDC lecture from Neil Druckmann and Bruce Straley about Naughty Dog approach to storytelling in Uncharted 2.
GDC lecture from Armando Troisi about Bioware Narrative Design in Mass Effect 2.
GDC lecture from Jonathan Perry about Bioware approach to cinematics design.
GDC lecture from Dave Feltham about Bioware approach to combining Narrative and Level Design in Mass Effect 3.