The DLC Lifeline introduced about 50 new traits, as well as added extra effects to those already featured in Storyline and Breakdown. Notably, all traits are now designed to have an effect on gameplay, as opposed to the large amount of "flavor" traits in previous gameplay modes.
For existing categories of traits, see the Traits page. Lifeline also introduces a few new categories, including but not limited to "Leader", "Conflict" and "Rank."
Leader: What type of leader the character is. This only takes effect when the character becomes the Commanding Officer of Black Friday.
Conflict: This is a hidden trait, representing the character's personality. Various visible traits give characters different personalities, that might cause conflict with the opposite personaliites resulted from another traits. For example, characters with the "Avid Surfer" trait will have the "Lax" trait, and will sometime clash with those with "Obsessive" trait (resulted from "Fitness Guru", among other traits).
Rank: When a CO (commanding officer) of Black Friday (i.e Alicia Hawkes) is killed in action, the character with the second highest rank will become CO. Only characters of certain ranks are qualified to be CO. If there is no characters that can fulfill the requirement, the game is over.