Bleeding Heart is a short, stand-alone prologue comic for The Glass Scientists. It tells the story of a formative incident from Dr. Jekylls youth and chiefly concerns an injured werewolf and (mostly) good intentions. While you do not have to read Bleeding Heart in order to enjoy The Glass Scientists, it may give you extra insight and backstory information of the main characters or at least lots of pictures of them making funny faces.
It was created in 2014 and launched a successful Kickstarter campaign to fund its printing. It is 28 pages long in black and white and can be bought and read digitally on Gumroad, or in print via StoreEnvy.