In Dishonored 2 (2016), Corvo wears a mask, while Emily just wears a scarf on her face. This is in reference to the fact that Corvo has experience with the rat plague
Bethesda on Twitter: "Celebrate Emily and Corvo w/ #Dishonored2's Collector's Edition feat.Corvo's mask replica and Emily's ring https://t.co/yFC0njzNgG" / Twitter