Research into plague motifs

Some of the most well-known imagery of the plague is that of plague doctors; in particular, their striking beak-shaped masks that were filled with perfumes that were said to help prevent them catching the disease.

http://upload.wikimedia.org/wikipedia/commons/5/57/Paul_F%C3%BCrst%2C_Der_Doctor_Schnabel_von_Rom_%28Holl%C3%A4nder_version%29.png

https://s-media-cache-ak0.pinimg.com/736x/00/0c/55/000c55815a383f0967b030ec98464d53.jpg

The shape of the mask also calls to mind the image of crows or ravens, two birds that were also regarded as symbols of ill-omen and death in the west. This was due in part to the birds' dark plumage and diet of carrion.

 http://www.animalphotos.me/bird/bird-crow_files/crow3.jpg

http://mikeatkinson.net/images/CarrionCrow06.jpg

http://upload.wikimedia.org/wikipedia/commons/7/78/Corvus_corax_%28Common_Raven%29%2C_Yosemite_NP%2C_CA%2C_US_-_Diliff.jpg

The bird-like appearance of the plague doctor mask mixed with the negative imagery of crows could create an interesting amalgamation. In addition, both are tied to the imagery of death. The dark plumage of the crows or ravens could create a quite literal personified 'Black Death' if incorporated into the antagonist design. 

Some other animals associated with the plague are rats, known to carry the fleas that spread the disease. 

http://deskofbrian.com/wp-content/uploads/rat-t9784.jpg

http://i.dailymail.co.uk/i/pix/2012/11/19/article-2235126-03D191EE000005DC-309_634x442.jpg

Rats are also associated with disease, but also uncleanliness, and aren't considered quite as unnerving an omen as crows. However, the flea-infested mangy fur and boils of infected rats could potentially be incorporated into the design. 

-Chloe