Werewolf!Robby who works days to avoid the moon and Vamp!Shen who works nights to avoid the sun.
Werewolf!Robby who's perpetually irritated by the smell of Vamp!Shen because werewolves naturally hate the scent of vampires. But, he finds himself always trying to find the faintest hints of Shen's scent.
Vamp!Shen who, frankly, thinks Werewolf!Robby stinks of wet dog... All musky, and gross, and kind of sexy. Robby's hoodie goes missing the five seconds he leaves it unattended during changeover.
Werewolf!Robby who frequently feels too much because he's just a big sad dog.
Vamp!Shen who's detached, and rather insensitive to quite a lot of the stuff he sees in the ED from his centuries of experience with guts and gore.
Werewolf!Robby who unintentionally gets territorial over Vamp!Shen. Finding Shen drinking blood; first he's mad that Shen is using the ED's blood, then that it's not his.