They can't shed BLOOD in their sacred city.
Game of Thrones Season 1, Episode 6
...brought you a pair of leather slacks
stained with chicken BLOOD.
The Big Bang Theory Season 6, Episode 9
You murdered him with BLOOD magic?
Game of Thrones Season 5, Episode 10
Why would a girl see BLOOD and collapse?
Game of Thrones Season 3, Episode 7
cleansed in their own BLOOD.
Westworld Season 2, Episode 2