The father of a boy who was found buried in a garden in Birmingham has told a jury he went "down a spiral of conspiracy" while studying for a degree in London.
Tai and Naiyahmi Yasharahyalah, aged 42 and 43, have denied causing or allowing the death of their three-year-old son, Abiyah Yasharahyalah.
He was found in a back garden in Handsworth, Birmingham, in December 2022.
Giving evidence on Thursday, Mr Yasharahyalah told Coventry Crown Court he had a spiritual awakening while studying in 2007.
The father, who was born in London but spent much of his childhood in Nigeria, told the court he began spending more and more time involved in conspiracy theories while studying for a degree in medical genetics in London.
He told the court he needed to "find some sense" in life.
Jurors heard that online research took up "most" of Mr Yasharahyalah's time.
Seven years later, he became vegan and started researching Igbo culture - the customs of a group living in southeastern Nigeria.
He said that, while reading into the history of his people, he started "another spiral of resentment".
He changed his name and moved to Birmingham shortly before meeting his wife at a music event in the city.
The couple started a relationship and got married in 2015, before Mrs Yasharahyalah became pregnant with Abiyah.
Mr Yasharahyalah told the court the couple intended to have a polyamorous relationship, to create a "community of families".
He moved to London, to "propagate" his culture and while there met a woman who became a "sister wife", eventually moving in with the couple at their home in Birmingham.
The court had previously heard the prosecution told the jury Abiyah died between December 2019 and January 2020 and would have been approximately three years and nine months old.
The prosecution claims he was found to have been "severely malnourished", with broken bones, rickets, anaemia, dental disease and stunted growth.
Mr and Mrs Yasharahyalah are also accused of neglect and perverting the course of justice.
The trial continues.