It is found on dead night stalkers. This item is used to craft antivenom and hydra at campfires. With the Old World Blues add-on, it can also be used to craft nightstalker squeezin's. Aside from finding it on night stalkers, nightstalker blood can sometimes be found on the corpses of members of Caesar's Legion. In Old World Blues, this item can be found in various laboratories throughout the Big MT.
- As of the most recent patch, night stalker blood was renamed to nightstalker blood (note the lack of spacing).