Blood can very likely represent life force or heritage:
Blood represents the essence of life and life-force (usually more physically than spiritually) - whereas the soul is thought of as immortal, blood is a sign that our soul remains here - in our bodies, in this life. Moreover, blood can symbolize the mortality of a person, or being, showing that they are able to experience pain and death.
As noted, blood can also represent inherited things - be they physical or genetic traits, or or even personality traits or an estate.
'It's in the Blood'