Lilly's Shadow Walker is the embodiment of her time as a SinWorker in the Great Void. It has the memories of the time before she left the Great Void and watched over the current Lilly. It is represented by the SinForce of Madness that seeks death. It has similar mannerisms to Lilly and finds the current Lilly to be unpleasant.
Background[]
Lilly first encounters her Shadow Walker during the events of Scaredy Cat Radar and attempts to get Lilly to release her true madness. It appears as SinForce copy made by Kant. After taunting Lilly about killing the illusion of Catherine, it disappears after realizing that it won't be able to take Lilly's body.
Advancement[]
After obtaining a Sin fragment, Lilly visits her Shadow Walker in the Sunken Grave. The Shadow Walker greets Lilly as a unexpected guest and questions why Lilly is currently restraining her madness due to a sense of justice and should wipe out everything in front of her. Lilly is stunned about her Shadow Walker and how she had reacted in the past. The Shadow Walker compares Lilly to a dog on leash and should release herself. However, the Shadow Walker states that it no longer has an influence on Lilly and cannot steal her body. It becomes annoyed with Lilly and decides to ignore her for a cup of tea.
During her second visit with the Shadow Walker, she asks if the person called "Lilly Bloommerchen" is a human. The Shadow responds that she is a monster and all that matters are fights for survival and takes pride in killing others. Lilly retorts that she is a normal human and has changed. Angered, the Shadow Walker tells her that if she abandons madness, then Lilly will become weaker and then inevitably die. Not fearful of dying, Lilly attempts to find a different path before returning the Shadow Walker.
On Lilly's third visits, the Shadow Walker considers her to be unpleasant and does not give a warm welcome like before. The Shadow insists the Lilly is a monster and cannot give up the madness. Lilly replies that the two are different: The Shadow Walker does not care about life in general and Lilly is sensing her own value. Within her own value, Lilly will fight to save others and is ready to change herself. Stunned, the Shadow Walker tells Lilly that she is only making a fool of herself and is a coward. In response, Lilly tells the Shadow that her death will be of her own choosing and time. The Shadow Walker then vanishes quietly.
SinWorker[]
After absorbing Erwin's clone, Lilly visits her Shadow Walker in order to obtain its strength. The Shadow appears to having tea and is annoyed with the current intruder. Lilly makes a direct approach to her Shadow Walker to lend her its strength where it readily agrees. However, the Shadow Walker warns Lilly that the more she uses SinForce, the Shadow will be to eventually take over her body. Lilly accepts the SinForce and returns to Grasscover Camp to channel energy. In her initial attempt to use SinForce, the Shadow Walker slowly erodes Lilly's mind and begins to take over. Fearful of the results, Miriam presses the VoidForce brooch to cancel the SinForce energy.
After taking Yoruhaka's advice to slowly getting used to SinForce, Lilly notices that her clothing has changed. She describes that the clothing is vulgar and does not want to use it as a medium to continue channeling SinForce.
After completing the SinForce stone, Lilly gains the ability to better control SinForce and summons her Shadow Walker to the Dirty Bookshelf. The Shadow Walker immediately recognizes Grasscover Camp and is disappointed in Lilly. It initially expected that Lilly would surrender her body to fight a tough opponent and did not expect the usage of the VoidForce Brooch. The Shadow questions why does Lilly needs its power and is exhilarated when Lilly replies it is for the sake of killing Kant. The Shadow replies that Kant is the only one who can kill her since his other toys were unable to. It continually attacked Kant in past due to hopes of being killed but he never bothered to kill Lilly. Excited, the Shadow Walker gleefully lends its strength to Lilly before it vanishes while laughing.