Dyson is Light Fae, and in his own way, is just as mysterious as Bo with his own complicated and not altogether pleasant history that he rarely speaks of. He spent at least two centuries as a warrior for the Light fae in the new world having come over with the Blood King imigrants and bears the scars of that and his long history as a lone wolf physically and emotionally.
A veteran detective on the human police force, he and partner Hale (a siren) use their combined skills to quietly protect the secret of Fae existence from inadvertent human discovery. This brings him into contact with rogue-Fae Bo who has killed a man in the Light territory. He quickly tracks her down and takes her before the Ash, the head of the Light fae clan. It is decided that she will be tested by both the Light and Dark fae, something she has little hope of surviving, and if she passes she will be given the choice that all fae are given at a young age - choose a side.
On his own conscience he takes it upon himself to do what he can to assist her in her test, letting her feed from him to increase her strength before the battle and giving her brief but useful advice on how to win. When she declares herself neutral between the clans he grudgingly agrees watch out for her and explain the complex Fae rules even as she proceeds to break them all. With Trick, to who he long ago swore his fealty, he knows that what is coming for Bo is more complicated, and more dangerous than she can foresee.
When Bo is badly wounded and in need of a feed to heal he offers himself which is the beginning of an increasingly complicated and intense love-hate, sexually destructive relationship with the succubus. Despite pushing her away emotionally, and telling her their casual arrangement has to end (at the behest of Trick who knows that his friend cannot love the woman and lie to her at the same time) he is incapable of turning her away when she comes to him even at the cost of his own health.
Secrets he's keeping, the increasingly difficult time he finds himself having balancing fae business, police business and Bo put his life in a spin that he barely keeps from rapidly going out of control and he finds himself offering to make the greatest sacrifice he can to protect Bo from her mother. He goes to the Norn and offers his wolf, but instead to save the woman he loves he sacrifices that love - and in fact as he will come to realize in time, his ability to love anyone.
Realizing what has happened he distances himself from Bo, and soon finds himself in an intense relationship with a woman from his past, the widow of his best friend and his former queen. But despite wishing to love her and building a life with her he is forced to realize that he cannot love Ciara. He cannot love anyone, as wolves mate for life and relinquishing his love for Bo to save her from Aife has left a hole inside him that can never be filled.
when he is forced to admit to Ciara that as much as he wishes he could he can never love her she leaves him. Making his isolation complete his own anger and recklessness result in losing his position with the police and pushes away Hale and Bo, and even separates him from Trick. An encounter with an Underfae who feeds on the despair and hopelessness of others, convincing them to kill themselves, leaves him raw and empty and even more alone as he takes off on his motorcycle to parts unknown. And that is when he finds himself at the Madonna Inn.