|First appearance:||Sympathy for the Devil|
|Portrayed by:||Jasmine Guy|
To Tess, Monica describes Kathleen as her friend when she first appears on the show. She says she once worked with Kathleen on "Search and Rescue" (assisting travelers in peril and the like), and that Kathleen was "the best", teaching Monica everything about "safe landings" (posssibly meaning safe ways for angels to insert themselves into the human plane of existence).
However, Tess quickly corrects Monica and says Kathleen is not her friend anymore. Monica then mentions "rumours" about Kathleen switching sides, which turn out to be true. Monica does not immediately appear very distressed about this, nor had she apparently investigated the "rumours" on her own, so to her, Kathleen had presumably been more of an acquaintance than a very close friend.
Nevertheless, she is sufficiently concerned to approach Kathleen later in the episode, asking, "So I guess it's true?" Kathleen, responding with superficial cordiality, says that she has found truth to be relative (a perspective Monica rejects as illusory: "you make it look that way"). Kathleen invites her to catch up later, "angel to angel", but Monica remarks that Kathleen is no angel anymore: "You know what you are!" (i.e., Kathleen has crossed the line to become a devil or demon). Monica's general attitude seems more like mild indignation than profound shock that a former friend of hers has joined the dark side, and her attitude encountering Kathleen may even appear slightly self-righteous.
Later in the episode, when Monica has been able to neutralyze Kathleen's nefarious intentions, she again approaches the fallen angel with a somewhat more humble attitude. She cannot understand how a being that had actually experienced God directly could ever walk away from him, as well as from other angels, and asks Kathleen: "Don't you miss us?" Kathleen grants that this may be so, remarking "What if I did?" She has still made her choice, she says, and claims to be having "too much fun" to turn back (though in the moment, she is plainly defeated and dejected).
Monica makes a remark that can be interpreted as either kind or passive-aggressive, saying: "I'll never forget who you were, who I loved, but I can't say I'm sorry to see you go." Kathleen responds that Monica has become a "hell of an angel" that she will not underestimate the next time they meet, and after this back-handed compliment, she leaves.