"It cuts through so many dreams and aspirations that you have for your child."
Tim Blackman arrived in Tokyo on Monday with his partner and Lucie's brother and sister, Rupert and Sophie, on a mission to bring her remains home.
The chief suspect in the case is 48-year-old businessman Joji Obara - who is already on trial for the rape of several women - but he has not been charged over Ms Blackman's death.
Mr Blackman, 48, from Ryde in the Isle of Wight, said his family hoped Japanese authorities would work quickly to bring Lucie's killer to trial.
"The discovery of her body gave us a strange feeling that we are actually going to find an end to the mystery," he said.
"An unnatural event of a child pre-deceasing a parent is hard to bear," he added.
"It cuts through so many dreams and aspirations that you have for your child."
Ms Blackman, who worked as a bar hostess in the Roppongi entertainment district of Tokyo, went missing last July.
Police found feet, a hand, a section of leg and her head, partly encased in cement.
Japanese police have completed forensic tests and Lucie's remains will be ready for transport in about a week.
Mr Blackman said he would show Sophie, 20, and Rupert, 17, the beach where the grim discovery was made, and areas of Tokyo and Miura where Lucie was believed to have worked and visited, to help them through the grieving process.
The family had set up a Lucy Blackman trust to help families whose children go missing abroad, he said.
The trust is appealing for donations to help the family in the short term, and also to build a fund to help establish ways to improve the safety for travelling children, Mr Blackman added.
Lucie's case has highlighted concerns about foreign women employed in Japan's night club and sex industries.
Many do not have proper visas, making it difficult for them to seek the protection of the law.
Cremation service
Mr Blackman said: "In the last six or seven months where the hostess business has been rather under the microscope with the spotlight on, there doesn't seem to have been any particular interest in changing the current system.
"And because the system has worked for a long time and the authorities know the girls are on tourist visas, they seem quite happy with that situation"
Lucie's mother Jane Blackman, who lives in Sevenoaks in Kent, arrived in Tokyo on Saturday.
A cremation service is being planned near Mrs Blackman's home in Kent.