MMA fighter "War Machine" has been found guilty of a string of charges brought against him after he brutally attacked his former porn star ex-girlfriend.

A jury in Las Vegas found Jonathan Paul Koppenhaver guilty of 29 violent offences on Monday relating to the sexual assault, kidnapping and battery of his ex-girlfriend, Christine Mackinday.

The former MMA fighter was charged with 34 federal offences but the jury were unable to reach a decision on two attempted murder charges involving Ms Mackinday and Corey Thomas who he found in her bed on August 8, 2015.

His lawyer conceded the 35-year-old was guilty on charges that relate to punching, kicking and threatening Ms Mack with a knife, and assaulting Mr Thomas in his closing statement.

The court heard Koppenhaver beat Mackinday for up to two hours, leaving her with broken ribs, a fractured eye socket, a lacerated liver, two missing teeth and severe bruising.

But had argued on the more serious charges of kidnapping, rape and attempted murder, that Koppenhaver's perception of right and wrong had been warped by the couple's disturbing fantasies and his drug use.

Mr Koppenhaver's lawyer has argued his client was overcome by rage when he found another man in Ms Mackinday's bed, which coupled with his abuse of steroids, the ADHD medication Adderall and anti-depressant Lexapro, caused him to lash out.

He beat Mr Thomas for ten minutes, choking him on multiple occasions, before unleashing on Ms Mackinday for up to two hours.

The defence presented text messages between the pair discussing rape fantasies and argued this "charming back and forth" created a norm of consent that allowed Koppenhaver to sexually assault or rape Ms Mackinday as "he believed it was okay".

The former MMA fighter was charged with 34 federal offences but the jury were unable to reach a decision on two attempted murder charges

However, the prosecution had painted a detailed picture of the abuse Ms Mackinday faced during their tumultuous 15-month relationship and the love that blinded her to the dangers of Koppenhaver's violent and controlling nature.

"He almost beat her to death and he threw a dog blanket on her as she was convulsing from a lacerated liver. And she still loved him – that's how bad the cycle is," she told the court.

The judge has ruled the two attempted murder charges a mistrial and Koppenhaver's lawyer said he feels "terrible" and will file for another trial.

Despite not being convicted on the most serious of the charges, War Machine still faces life in prison with no parole.

Ms Mackinday cried on the trial as she was accused of revelling in the fame that came after the assault.

He was found not guilty of three charges including burglary with use of a deadly weapon, sexually motivated coercion and battery with intent to commit sexual, according to Fox 5.