Kill to Death Ratio (abbreviated KDR in challenge descriptions) is the ratio of how many enemies (other players) a player has killed within a match compared to how many times they have been killed themselves (by other players). There are three Multiplayer Challenges that require a player to achieve a 5:1 kill to death ratio in different multiplayer game types. These are covered on the Kill to Death Ratio Challenges page.

Note that if an enemy player leaves a game session before it is complete, kills and deaths related to that player are removed, altering the kill to death ratio.