Kat is one of the primary supporting characters in DMC: Devil May Cry. She helps Dante throughout the game, making him portals into Limbo, giving him tips about his objectives and finding him a way out of Limbo. She's part of the "terrorist" group known as The Order, along with Vergil, the group's leader.
Kat also makes an appearance in Playstation All-Stars Battle Royal as a miniature minion.
Role in DMC: Devil May Cry
Kat is first introduced in DMC as a mysterious, hoodie wearing character who comes to Dante's trailer to warn him about an impending demon attack. She helps Dante make it through Limbo before escaping with him. She brings him to The Order, a secret organisation who strives to destroy the demon Mundus and free humanity from his grasp. There, Kat makes Dante meet with Vergil, his brother. Together, they embark on a quest to destroy Mundus's key infrastructures (the Virility factory and the Raptor news network).
Kat is initially shy to Dante before opening up about her past and the nightmares that haunt her. She explains that her father was a demon and used to physically beat her. She would escape into Limbo in order to escape the beatings (her previous experiences in Limbo end up being vital to Dante's quest as Kat, through her out of body experiences, was able to scout out the Virility factory). In Limbo, she found Vergil, the leader of The Order who recruited her after getting rid of her demon father. Vergil taught Kat how to create seals that let individuals access Limbo. Kat eventually came up with a way to condense the complex spells necessary to creating a seal into a can, which she uses to create seals for Dante throughout the game. Kat also has other mystical devices. She has a ball like object which Dante jokingly refers to as an egg timer, which switches gravity in Limbo for a set amount of time. Kat is also a medium, she can see into Limbo.
Kat finds herself under heavy fire when SWAT forces (lead by Mundus) raid The Order's compound. Kat initially succeeds in hiding from the armed assailants as her colleagues are brutally murdered. Dante (who's in Limbo) manages to reach her and succeeds in delaying the advancement of SWAT by bringing down objects within the base thanks to Kat's spray can. The two eventually make it to the compound's server room (which is a dead end) where Dante saves Vergil (who's also in Limbo). Vergil makes Kat delete all the data on the servers (he's unable to do it from Limbo) as SWAT teams begin breaching the door. It becomes clear to Dante, who'd become especially fond of Kat, that the assailants reach Kat. He tells Kat to get on her knees with her hands up, convinced that she'll be captured and that he'll go to rescue her. Instead, the SWAT breach the door, shoot Kat in the back, beat her to, before dragging her body away.
By some miracle, it's revealed that she survived getting shot and beaten and is now being brutally tortured by Mundus. Despite the torture, she doesn't give anything away as to where Vergil and Dante may be. Dante comes up with a plan to rescue her, he intends on capturing Mundus's mistress (who's carrying Mundus's spawn) and exchange her for Kat. Dante succeeds in kidnapping the mistress and him and Vergil go to the rendezvous point to trade her for Kat. As the trade is underway, Vergil shoots the mistress, thus killing Mundus's spawn. Dante manages to get to Kat despite the chaos and they all escape.
Kat then helps the two brothers to concocte a plan in order to infiltrate Mundus's lair. Throughout the level where players raid Mundus's building, her voice can be heard during the planning stages and her chalk drawings appear within the game's environment, telling Dante where to go.
After successfully defeating Mundus, Kat discovers what Limbo looks like when it collapses into the real world. A power hungry Vergil, wishes to take Mundus's place, discrediting what Kat did on the account that she's a human. As Dante and Vergil fight, Kat hides. Once Dante gets the upper hand, she appears and convinces Dante not to kill Vergil (despite the fact that Vergil already has Dante's sword halfway through his chest), telling him that he should do it for her. She convinces Dante not to kill Vergil (who makes his escape) and comforts Dante as the game ends.