Mick Philpott stuck two fingers up in court as the Judge told him he was a "disturbingly dangerous man" and would be sent to jail for life.
Speaking exclusively to ITV News, Dawn Bestwick said jail wasn't good enough for MIck Philpott and that "as a coward" he "deserved to die".
The judge has delayed her sentencing to "reflect further" on the trial Mick and Mairead Philpott and friend Paul Mosley.
Paul Mosley, the friend of Mick Philpott, chose not to give evidence during the trial.
He was sentenced to 17 years in jail for his part in the manslaughter of six children who died in a house fire in Derby last May.
Paul's sister, Angela Mosley, has told ITV News Central that she doesn't think her brothers sentence is long enough.
The sister of Mick Philpott described how she effectively buried her brother today as she saw him sentenced to life for killing six of his children in a house fire in Derby. Speaking exclusively to ITV News, Dawn Bestwick said jail wasn't good enough, and that "as a coward" he "deserved to die".
Dawn Bestwick said: "They [the children] had a life. He [Mick Philpott] took that from them, he had no right. I hate him, I hate him so much. He's hurt us so much, it's not fair. He doesn't deserve to breath God's air. He deserves to die for what he did - and so do the other two. They were so cruel.
"It's not human, he should die for what he did. All three should rot in hell for what they did. The pain we have to live now, the grandmothers, the grandfather - they're the ones suffering too. The other siblings, Lord knows how they're going to get through this. But we're a strong family."
Watch the interview in full here shortly.
Mick Philpott holds his heads in his hands as the sentences are read out at Nottingham Crown Court. He was jailed for life with a minimum term of 15 years after being found guilty of killing six of his children in a house fire.
Mairead Philpott wept in court as she was sentenced to 17 years behind bars for the manslaughter of six children in a house fire.
Members of the public gallery shouted at Mick Philpott as the judge finished her sentencing. In response, Philpott smiled and made an obscene gesture as he was led from the dock.
Angry shouting greeted the Philpotts as their prison vans left Nottingham Crown Court this morning.
Mick Philpott has been deemed a child killer and sentenced to life in prison for the deaths of six of his own children.
His wife Mairead, and their friend Paul Mosley, have been sentenced to 17 years.
– Judge Mrs Justice Thirlwall
You craved attention, you enjoyed the limelight. You courted publicity. You were and remain the centre of your world and it is plain that you require everyone in your life, but particularly the women to make sure that you remain at the centre of their world.
Your needs and desires took precedence over everything, everyone else, including your children.
You so arranged your life and theirs so that everything was done for the pleasure of Michael Philpott.