Bailey Boswell, 26, has joined her boyfriend Aubrey Trail, 54, on deathrow after being convicted of murdering 24-year-old Sydney Loofe in November 2017.
The couple were said to have targeted other young women describing themselves as a vampire and his witch queen.
They allegedly chopped Loofe's remains up and scattered them in bin bags across rural roads in Nebraska, US, after killing her in November 2017.
Loofe reportedly went on a date with Boswell after the two met on the Tinder dating app and was excited to see her again.
But she was strangled to death on her second date.
A woman named Ashley Hills took the stand in Boswell's trial earlier this month and claimed that Trail said he was a vampire, and that Boswell was his witch queen.
The two reportedly spoke often at their home of killing and witchcraft, according to Hills. She said they told her she, too, could gain magical powers if she agreed to kill someone.
She said she initially agreed to meet Trail because Boswell said he was her "sugar daddy" and said she was initially interested in being a part of the "witch coven".
The pair allegedly told her: "To get your power, you would have to breathe in someone's last breath."
In his trial last July, Trail claimed that Loofe was choked to death accidentally during a sex game between the three of them.
The court heard she and Trail had lured other women using dating apps before, and that the two claimed to be in charge of a witch coven, the Lincoln Journal Star reported.
Trail is set to be sentenced in December, while Boswell's sentencing date has not yet been determined.