Loner, Richard Huckle, 30, has admitted an unprecedented number of child sex offences and faces multiple life sentences at the Old Bailey.
In court, it emerged he attended several churches in the UK before leaving to work as an English teacher among poor Christian communities in Kuala Lumpur.
He gained trust by pretending he was committed to God and used it to find young people to abuse.
Up to 200 children as young as six months were left alone in his care because parents believed he was a Christian missionary.
The freelance photographer from Ashford in Kent began the abuse on a gap year to south east Asia at the age of 19.
He went on to post a stream of pictures and video of himself raping his young victims which were shared worldwide on the dark web.
He even set up a crowd funding enterprise inviting other paedophiles to pay Bitcoins for access to images and was in the process of publishing a paedophile's guide to abusing children in poverty-stricken areas, the court heard.
In discussions online, he bragged: "Impoverished kids are definitely much easier to seduce than middle class Western kids."
Acting on information, Huckle was arrested by the National Crime Agency when he touched down at Gatwick Airport en route to spend Christmas at home with his family in 2014.
Prosecutor Brian O'Neill QC said Huckle's computer equipment was seized and he was bailed on condition he return to his parents' home.
Officers had also searched the home of Huckle's parents.
He refused to answer officers' questions, but the next day his mother asked him about the allegations and he admitted he had sex with children aged between three and 13.
She called police and begged them to arrest her son.
Mr O'Neill QC said: "His mother was both extremely upset and extremely angry. She and his father called the police and asked them to take their son away.
"Both have made witness statements in support of this prosecution."
As well as the draft of Huckle's paedophile manual, they found a "Pedopoints" ledger in which he awarded himself marks for acts of depravity with children.
A total of 191 children were mentioned in Huckle's scorecard.
Huckle has admitted 71 child sex offences, including multiple rapes, against 23 identified children aged between six months and 12 years old.
Twenty two of the charges carry life sentences.
A further 20 charges will lie on court file when he is sentenced by Judge Peter Rook QC on Friday.