The High Court in Machakos jailed a man for 20 years for defiling his 13-year-old sister.
Judge Jaden Thuranira rejected the man's mitigation on claims that he was 'possessed by demons' when he abused his younger sister.
He had been convicted by a magistrate's court after it was found that he was in his right mind when he committed the offense.
He later appealed the ruling claiming that the lower court erred when it ordered he be jailed.
The man had admitted defiling his sister on February 25, 2012, adding that the same demons had caused his girlfriend to run away.
He told the court the same demons had plagued him and blinded him to see his sister's face as that of his runaway girlfriend.
He argued that the demons used to sleep with him and at one time he ran away from home. However, when he returned home the demons came back.
"The appellant in his defence appears to have admitted the offence but seems to say that he saw the face of his girlfriend. The appellant then talked about being plagued by demons and asked for the court's forgiveness. The trial magistrate was right in reaching the decision that the admission of the offence was unequivocal. The prosecution proved their case beyond reasonable doubt," Justice Thuranira ruled.
He added: "The appellant was evaluated by the psychiatrist and found to have no mental disorder."
The two were living with their grandmother and on the faithful day of the offence at around 11am, the man asked the girl to bring him water. She left for the kitchen and returned with the water. She found him holding a machete, which he used to threaten her to buy her silence.
The court was told that he defiled her several times until midnight. The following day, at 6am, the girl left the place to her elder sister's house where she narrated the ordeal.
The incident attracted villagers who wanted to lynch him but the area chief saved him.