The children, Duwayne, 13, Jade, 10, John, nine, Jack, eight, Jesse, six and Jayden five, died in May 2012 after their father started a blaze which swept through their Derbyshire home.
Now, their paternal grandparents have spoken of their relief after the memorials were put in place in their local cemetery.
"They're beautiful. I just wish they weren't here," the children's devastated grandmother Peggy Philpott, 86, told the Sun.
Grandad Jim Duffy, 64, said the last year had been a nightmare, but that seeing the headstones in place was a 'real relief'.
"They're a real tribute," he said.
The six children each have a personalised stone engraved with an individual eulogy.
Jayden is labelled a 'miracle baby', while John is described as 'caring', Jade 'beautiful and creative', little Jesse 'bouncy', Jack 'shy' and teenager Duwayne 'talented'.
The money for the marble stones was raised by the local community.
Mick, 56, and Mairead Philpott, 31, and their friend Paul Mosley, 46, were convicted of the children's manslaughter in April. Philpott was given a life sentence, while Mairead and Mosley were jailed for 17 years each.