Original: The executor of the law of blood-revenge who personally put the initial aggressive killer to death was given a special designation: go 'el haddam, the blood-avenger or blood-redeemer (Book of Numbers 35: 19, etc.).
Simplified: The person who put the initial aggressive killer to death was given a special name: go 'el haddam, the blood-avenger or blood-redeemer (Num. 35: 19, etc.).