Wanderer is a Soul who is implanted into Melanie Stryder's body by Healer Fords Deep Waters. Wanderer is highly respected among her kind, because of her experience and bravery in past hosts' lives. She has lived on eight different planets before coming to Earth, including having been born on the Origin, the Souls' home planet, while the average number of planets each Soul tests out is only two. This is why she is named Wanderer, since she never settled on a planet for more than one lifetime, she wanders around the universe. Because of her excellent credentials, she is selected to be inserted into Melanie's body -one of the few remaining 'wild' humans-, which is expected to be a difficult and painful experience due to the immediate memory of her attempted escape from the Seekers by falling suicide.
It turns out to be even more distressing, since Melanie's consciousness hasn't disappeared as it should have (later revealed to be because she knew about Implantation beforehand). Wanderer has access to most of Melanie's memories except those which would endanger her human lover Jared, and has none regarding Melanie's brother Jamie. Melanie has thrown up a wall against Wanderer, who is annoyed, frightened, and frustrated by her presence. She struggles to adjust to her new life as a human, but as time goes by, Melanie's memories and feelings for her lover, Jared, and her younger brother, Jamie, bec ome overwhelming and she decides to travel to Phoenix to consult Healer Fords about reimplantation. The Seeker tries to persuade her to take a shuttle by taunting her -which is very unusual for souls- but Wanderer insists on taking the car ride.
During the drive through the Arizona desert, she joins Melanie in viewing/feeling deeply emotional memories/feelings of Jared and Jamie which she previously had no access to due to Melanie's interference. Wanderer finally breaks down under the onslaught of emotions and admits to Melanie that she loves them too now, and thus has no choice but to be reimplanted to escape the longing and pain from not being with them. They see Picacho Peak, which reminds Melanie of her Uncle Jeb's mysterious directions to a safe place, given to her just before the invasion became known. With both of them overwhelmed by the possibility of Jared and Jamie being close by, Melanie eventually persuades Wanderer to embark on a dangerous trip in the desert to find them.
After days of wandering in the desert, Wanderer suffers from severe dehydration and eventually collapses un der a tree. This is where she is found by Uncle Jeb, who gives her water, saving her from certain death, and transfers her to his hide-out, a complicated system of underground caves which were once lava tunnels from a volcano. It turns out there are many more humans living in hiding with him, but they are all hostile towards Wanderer and consider giving her to Doc for experiments. When she notices Jared, Melanie wildly pulls Wanderer towards him but he punches her before she reaches him. Wanderer is saved from Doc by Jared (who is very confused) who together with Jeb keep her safe but prisoner in a small cave usually used for food storage.
Her life is in Jared's hands, who cannot make up his mind, while she keeps the presence of Melanie a secret out of fear of being thought a Seeker (which would mean immediate death) as only Seekers lie to humans. Eventually, Jared and a couple of men (including the angry and brutish Kyle), leave on a supply raid during which Jeb allows Wanderer to move freely in the caves. Slowly, Jeb forces her presence on the survivors to start getting them used to her presence and to realize she is not a danger to them, while Jeb and Jamie find out her secret about Melanie.
By the time the men are back, Wanderer is nicknamed "Wanda", has taken over unofficial teaching duties about the other species in the Universe and their planets every evening in the kitchen and is encircled by a number of friends who stand up for her. Jamie and Ian (Kyle's more rational twin brother) in particular try to protect her. She begins to stay in the hospital with Walter to ease the pain of his slow death, as he is a survivor dying of end-stage cancer, who (in his delirium) believes she is his wife.
Despite all this, she is eventually attacked by Kyle while cleaning herself up so she can say goodbye to Walter before Doc gives him a morphine overdose to save him the pain. Despite being severely injured during the attempted murder, Wanda saves Kyle from a collapsing floor, is forgiving, and opposes Kyle's punishment. Her kindness and selflessness slowly win over Jared, who starts to believe her about Melanie being present, but at the same time, Ian reveals he has fallen in love with her. The humans have been kidnapping Souls and attempting to surgically remove them from their human hosts by dissecting them.
It always fails, however, as the Souls' attachments shred the hosts' brains during the torturous procedure. Wanda makes this discovery and is immediately and horribly traumatized and scarred forever by the experience of seeing twisted and butchered Souls strewn about the hospital. She becomes catatonic with mourning for three days and is joined only by Ian, who implores her to eat. She eventually comes to, and after learning of Jamie's fever and infection, realizes she has lost Melanie due to the trauma. Ian attempts, and Jared succeeds, in soliciting a massively overwhelming emotional response from Wanda's body through passionately kissing her, bringing Melanie back into being.
Wanda then escapes with Jared to go find Soul medicines for Jamie's infected leg after the humans (mistrusting Wanda) tell her he must simply fight it off, which he obviously will be unable to do. She succeeds, and though she has the absolute most perfect opportunity, does not expose the humans to the Seekers. Now trusted completely as one of them, she is no longer a prisoner, and starts going out and bringing back food, medicine and supplies that humans formerly had no access to.
The appearance of the Seeker and her murder of Wes, however, makes her realize that if she does not reveal the secret of how to safely remove a Soul from a host, the humans will most certainly kill the Seeker as they have no other option. She understands that this will mean her own removal from her host, Melanie. She decides that she no longer wishes to be a parasite, to steal someone else's life, and plans to die instead once she has been removed. For the sake of Melanie, Jamie and Jareds' happiness, despite Ian and Melanie's desperate protest, during which Wanda realizes she loves Ian too.
She sticks with her plan and goes to Doc, despite a tribunal in which she is ruled too useful to remove, but after her removal from Melanie's body Jared saves her at the very last moment. Eventually Tails transfered her to a new body (a hedgehog's) whose original owner was a host for a greater period of time than she was free (therefore her personality would never return) and she is able to live happily in the human community, becoming Ian's lover and a new member of Sonic's team.
She is voiced by Milia Kunis
She is portrayed by Saoirse Ronan (Inside Melanie's body)
Movies she appeares in
Sonic Storm Adventures of The Host