Here "blood" represents the person who was killed. An "avenger of blood" is a close relative of the person who was killed. This relative is responsible for punishing the murderer. (See: [[rc://en/ta/man/translate/figs-metonymy]])
Someone being very angry is spoken of as if anger were something that could become hot. Alternate translation: "and being very angry" (See: [[rc://en/ta/man/translate/figs-metaphor]])