Rowena was initially antagonistic towards the Winchesters as she saw Crowley's relationship with them as diminishing his power. The Winchesters often called on her help with magic, and Rowena assisted when she saw a benefit for herself. Over time, she became an ally in their battles, albeit motivated by the benefit she saw for herself in helping them. Rowena had a particular bond with Sam -- they were both tortured by [[Lucifer]] and saw his true face, and share the struggle of living with that experience.
In 2018, Rowena began killing people and their [[reapers]] to get [[Death]]'s attention, as she blamed herself for Crowley's death and the path that her abandonment led him down in life. During this, the reaper [[Jessica]] reveals that in the book [[Death]] keeps on her, it is written that she will die by Sam Winchester's hand. While
death refused to bring Crowley back, the experience ended with Rowena deciding that working for the greater good will be her redemption. She subsequently aided the Winchesters in their efforts to return to [[Apocalypse World]] and on occasions when they needed her expertise on a situation or case.
In 2019, after the release of the [[Hell Ghosts]] upon the world, Rowena chose to sacrifice herself to save the world by using her own body to
cast all of the souls and demons back into Hell. At Rowena's request, and with great reluctance, Sam was indeed the one who fatally stabbed Rowena. Following Rowena's death, Sam inherited [[Rowena's Spellbooks|her magical stash]], as it's suggested that she intended.
When the Winchesters and Castiel return to Hell in search of [[Michael]], they discover that Rowena's [[soul]] took up the empty position of Queen of Hell. Retaining her old personality, Rowena aids the Winchesters once again and even urges Dean and Castiel to mend their broken relationship.
[[Spells]] created by Rowena included:
* [[Resurrection Charm]] – A subdermal sachet of powerful magic that is sewn into a person's body. Once the spell senses the life-force of the individual ebbing, the magic kicks in as a purple glow and works its way through the body, repairing the damage and resurrecting the individual. Rowena uses it twice herself, and has to remove one so that Sam can kill her.
She also gave one to [[Ketch]], who used it after [[Mary]] shot his head.
* ''Defigere Et Depurgare'' – Known in its English translation as "To bind and purge," this is a spell created by Rowena in the 18th century that causes demons to liquefy and get coughed up out of their meatsuit. It appears that the spell binds the demon to its meatsuit to keep it from escaping as it begins to liquefy the smoke into a sludge-like substance and be purged from the host body. The spell was only practiced by Rowena, and before she used it to kill Raul, it hadn't been seen since the 18th century. Sam attempted to use a strengthened version of the spell to kill Crowley and satisfy his deal with Rowena, but while the spell manages to temporarily incapacitate him, Crowley eventually overcomes the spell's effects and sets the hex bag on fire.
bestiarum'' – A spell Rowena referred to as an "attack dog spell," wherein the witch places a hex bag in the hands of someone and recites "impetus bestiarum," turning the object of the spell into an animalistic killer who can be directed to kill a particular individual. The spell will eventually kill the person it is cast on unless the spell is reversed by the witch who inflicted it by reciting "desiste ad levo onus tuum."* Resurrection Spell - A spell devised by Rowena and completed by Sam Winchester which causes a spirit to become human. Unfortunately, the spell could only be used once as [[Billie]] closes any loophole that cheats death.