The Red Shield is an organization dedicated to killing Diva and Chiropterans. The organization was started by the grandchildren of Joel Goldschmidt after he as well as all the living members at the Zoo were slaughtered by Diva.
Leadership of the Red Shield is passed down from father to son, with the current leader being Joel Goldschmidt VI. Many of its members have endured tragic encounters with chiropterans in the field and all members of the Red Shield carry an item containing a piece of red crystal taken from the crystallized body of destroyed chiropteran.
According to the Blood+ light novels, the organization's name is taken from the idea that the members are Saya's shield of blood, incapable of killing chiropterans themselves but willing to die to protect Saya.
- Ironically enough, Rothschild (the historical family that Diva's five chevaliers are each named after) means 'red shield' in German.