Cait was born in 2261 to a distant and abusive family of Irish1 descent. She had tried to run away from her parents twice; the first time, she was locked outside in a shed, the second time, they broke one of her legs. On her 18th birthday, Cait's parents sold her into slavery. For five years, she stole small sums of bottlecaps from her owners, until she had enough to buy her own freedom. In a pique of rage, she returned home to seek vengeance on her mother and father.
At some point after she left home, she began using psycho, developing an incurable addiction. Sometime later, she arrived at the Combat Zone in Boston, and was hired by owner Tommy Lonegan as a cage fighter, soon becoming a strong and ruthless fighter. In 2287, a raider gang moved into the area, which then required Cait to buy friends to make life easier, making the cage fighter mistrustful of selfless offers of kindness.
Sometime later, the Sole Survivor arrives at the Combat Zone just as Cait is winning a match and subsequently interrupts the rest of the event. After the Sole Survivor defeats the raiders in the building, Tommy discusses Cait's drug addiction and offers them Cait's contract.
Agreeing with Elder Maxson's order to hunt down and execute Paladin Danse at the start of Blind Betrayal. Staying true to this intention during later conversations (e.g. with Haylen) and eventually going through with it earns even more approval.
Telling Deacon 'Someone has to stop them' when asked if willing to risk some danger to stop the Institute and their nefarious schemes (this only happens after telling Desdemona that you would not take a bullet for a synth at the end of Road to Freedom).
She will try to comfort the player character if taken to the corpse of Nate/Nora in Vault 111.
Cait will dislike all four of the first set of dialogue options during the Minutemen quests to help settlements with raiders.
Cait will actively use Psycho, Jet, RadAway and other chems in her inventory. Since it was explained she was an addict when meeting her, it might be beneficial to keep her stocked up as she appears to get friendly very quickly, and it might improve her usefulness in fights.
If Cait has any Psycho or Jet, one can sometimes see her using it before completing her personal quest.
Although not always, Cait may react negatively after completing her personal quest "Benign Intervention" if the player character uses chems in front of her. She will berate them for being a "hypocrite" for using them after helping her to cure her Psycho addiction.
The Sole Survivor may raise Cait's affection level by removing their own clothing and fast traveling between safe locations.
Cait likes when the player character gets naked. Cait's affection level can be quickly raised using Home Plate in the Diamond City market by repeatedly exiting the house, sitting in a chair for two hours and then re-entering the house and sleeping for two hours in a bed. The affection level will be raised both when exiting and entering the house.
Cait will disapprove of joining any of the factions until the second act of the main story when the Brotherhood of Steel comes in. After this she will no longer disapprove of joining the Brotherhood of Steel.
Cait asks Takahashi to serve her a drink on their first meeting, but she doesn't get it as Takahashi only serves noodles in the Diamond City market.
Cait's dialogue while exploring several of the vaults indicates that she is already familiar with the Vault-Tec experiments and the true purpose of the vault network.
When replaced by certain companions, Cait is prone to make flirtatious comments, such as Piper, for whom she will say it's "too bad they can't make it a threesome," or Deacon and MacCready, whom she refers to as "handsome." She also tells Hancock that if she ever decides to "go ghoul," he'll be the one she calls.
Without completing her personal quest "Benign Intervention", the maximum level of affinity that can be reached with her is "999". This means that to be able to get her perk "Trigger Rush", the player has to complete her quest first.
pcps4xboxone Cait's quest might not trigger after her confession about her addiction. Taking another companion, sending her back to a settlement, and then talking with her should trigger the quest. (It may have to do with her being flagged as a companion) For more info about this bug, read Benign Intervention.[verified]
pc Cait will talk about wanting to "lower the dosage" if she thinks she is being followed in combat after Vault 95.[verified]
pcps4xboxone During Cait's companion quest, Cait may begin to randomly collapse as if incapacitated during the dialogue. This will continue following completion of the quest.[verified]
pcps4xboxone Ordering Cait to pick a floor safe when there is an object between the safe and Cait may sometimes cause her to pace aimlessly around the area.[verified]