Bill Collins was an undiagnosed psychopath, being plagued with extremely violent and depraved thoughts all his life that stemmed from mental illness that ran in his family, mental illness that was also amplified by extreme abuse thrusted onto him by a strict, Naval officer father and religious trauma given to him by his devout, schizophrenic mother.

Bill struggled to keep his violent impulses in check on a day to day basis but he did his best to keep his demons at bay for the sake of his family and career but he would have moments where he got to "vent" his repressed thoughts such as by torturing animals whether they be stray pets or animals he would find on his frequent hunting trips.

He also had a reputation of being very "overzealous" as police officer due to his constant battle with violent, intrusive thoughts, he was the kind of guy you would think of when you thought of the phrase "police brutality" and his partner, Nathan Cole had to reel him in on a nearly daily basis.

It was keeping these violent desires at bay that lead him to being very depressed and shameful of himself and he would frequently try to drown these feelings either by distraction himself with hobbies or by getting shitfaced at the local pub but all that would change when he would meet someone very special…

Mona broke into Bill's house to murder him and his family but was ambushed by Bill, anticipating that she would come after finding her painting in his home, which at this point, was a calling card of her's, planting one of her paintings in a victim's home, sometimes weeks before actually committing the murder. It helped that Bill was following her case, not in the sense of doing investigative police work but out of admiration.

Bill pinned Mona to the floor with his full weight on top of her lanky, emaciated form, hand wrapped around her throat and a knife pointed at her heart. Bill was literally drooling like a wild animal as his dilated pupils stared into Mona's black, abyss-like eyes, barely able to contain his excitement as he would finally be able to live out his murderous thoughts on a real person. However, Bill's murderous intent would only be match by a sudden wave of arousal.

As Mona and Bill looked into each other's eyes, they saw themselves in the other and for the first time in Mona's life she felt true love, she found someone who truly "gets it". Mona gave Bill a crooked smile and said "go ahead, do it", her voice laced with twisted, sultry arousal which Bill picked up on almost instantly.

Bill's wife than came into the room where she saw him pinning the intruder down but before she could say anything, Bill lunged at her and slit her throat, much to Mona's surprise yet equal delight. Bill, with almost no questions asked would then assist Mona in killing his own daughters and help dispose of their bodies.

It was actually Bill's idea to cut off one of his arms, doing so in order to add it to the blended up slurry that was now the rest of the Collins family in order to throw off investigators and lead them to believe he was dead. It was shortly after that where Mona told him to cut off his own face, acting as a symbolic gesture of letting go of the false life he lead before meeting her and embracing his true self, which he did.

Bill was never happier, the man he pretended to be was gone and he has fully embraced what he was always meant to be, a monster. Mona found what every artist needed, a muse and Bill found what he was truly missing from life, a soulmate. Mona truly understands Bill and loves him for the bloodthirsty animal he is and Bill will always have unrelenting love and devotion towards Mona for finally freeing him from the "delusion" he was living.

Mona and Bill at this point became a certified, serial killer power couple. Bill does most of the murders, acting as a muse for Mona's paintings. Mona has the utmost love and admiration for Bill's brutality, considering his murders to be high art all on their own.

Bill meanwhile deems Mona's methods of killing to be as beautiful as she, focused yet brutal and overflowing with originality. Overall, Bill's murders like a wild animal, chaotic and brutal, while Mona is more focused, planned out and applies more twisted creativity when killing.

They were truly meant to be.

As Mona and Bill's relationship progressed, becoming more and more depraved as a result, Bill's mind would also deteriorate, the former police officer becoming more animal like to the point where he would speak only in animalistic growls and willing to attack anything that moved in order to protect his beloved Mona, a result of fully embracing his Id combined with a diet composed completely of medication cocktails and whatever bodily fluids Mona gives to him as a treat.

Mona, perhaps unsurprisingly, was perfectly fine with having a guard dog for a boyfriend now, going as far as giving him a collar.

Bill Collins, once a highly respected and revered officer who could've gotten help for his internal struggle he was just more open for his mental health, threw his life away to fulfill his darkest fantasies and eventually reduced to becoming the pet of the most depraved and prolific serial killer in the past decades… and all for it to end by him being shot to death by his former partner.

And yet, if given the chance, he would absolutely do it all again.