A Utah polygamist has been arrested for sending two of his wives dressed up as ninjas to try and kill a teen he sexually abused.

Kain Blackwing, 47, was charged with aggravated murder, conspiracy to commit aggravated murder and attempted aggravated murder, KSL-TV reported. He has not submitted a plea for the charges, which were filed Thursday in Beaver County, Utah.

Blackwing, who is currently serving a 15-year jail sentence, was convicted in 2014 for sexually abusing a then-14-year-old girl.

Four days before the 2014 trial, two women dressed as ninjas with black masks reportedly broke into the teen's home in West Jordan, Utah.

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They were armed with a stun gun, knife, screwdriver matches, syringes, plastic wrap tourniquets and formalin.

Their bizarre toolkit served a purpose. After spending time monitoring the girl's home the two women planned to suffocate the teenager with the plastic wrap and stage a heroin overdose for the other two occupants.

But the fiance of the girl's mother (who is also Blackwing's half-brother, according to the New York Daily News) was home and fought off the so-called "polygamist ninjas."

"She came at me with a stun gun, and I instinctively blocked it with my arm, and I hit her in the head, then proceeded to jump on top of her," the man told KUTV about one woman.

"I grabbed my sword on the mantle, unsheathed it and told her to sit down, that if she moved, she would lose body parts."

The engaged couple told police they recognised the attackers, even with the ninja disguises.

The police responded to the scene and detained the two women - Raven Blackwing, 22, and a 19-year-old female - who turned out to be two of Kain Blackwing's purported "sister-wives," according to court documents.

The women told police that Kain Blackwing had sent them to kill the teen because he believed that he would be released if she could not testify at the trial. According to authorities, they discussed the plot while he was in jail using code words.

They plotted the attempted murder for 11 weeks, using a code where the killing was called "playing a video game." They referred to their targets with names like "Juggernaut," "Boss" and "Guards."

The two women were convicted in 2015 of aggravated burglary, aggravated assault and retaliation against a witness or victim charges. The youngest was put on probation and Raven Blackwing got a 15-year prison sentence.

Last week, Kain Blackwing's third wife, Theresa Baker, 25, was arrested for concocting the scheme.

The sexual assault of the teen is not the only charge Kain Blackwing has faced of this nature - he also faces similar charges from the youngest sister-wife, who was convicted for the attempted murder. Police say he met that woman when she was 17 and started a sexual relationship with her.

She claims to have met Kain Blackwing when she was a teenager and he taught her "fighting and survival skills."

He allegedly claimed to have been a "Shen lord," a god and required his wives to call him "Lord."

He also allegedly told the women that "if he ever bonded with a woman she became his and the only way out of the relationship was death," the charges state. He eventually "claimed her" as his wife.

For that case, Blackwing faces charges of rape, forcible sodomy and forcible sexual abuse, and he is scheduled for a court hearing on February 28.