be after/out for somebody's blood

be after (one's) blood

To seek revenge on another person. He hit my car, so I'm after his blood now.
See also: after, blood

be after/out for somebody’s ˈblood

(informal, often humorous) want to hurt or harm somebody, especially as revenge: They have been after my blood ever since I accidentally damaged their car.
See also: after, blood, out