Act 1: Childhood
She died because of Auswahlen, not because Lil killed her.
Lil would not kill her as they get along the most, but its just to her misfortune that she got struck by Pepe's 'love'. Ewww, gross.
For Meninas, that's a good enough excuse to fucking die, so she did.
But she was reborn.
This time, her life did not revolve around anything spiritual.
She was reborn to happy parents who doted on her and treated her preciously, naming her Tsunami.
She didn't mind this life as she never had 'childhood' her whole life as all Quincies are soldiers from birth.
However, one day, her father came home with an old man. His boss from work, he says.
However, when he was to touch her with a flaming finger...she quickly analyzed the energy and how it works...
Oh. Hell. No.
She punched his arm. Hard.
She heard a satisfying crack as her father and the old man gasped.
'Igh!' the old man cried in pain as Tsunami jumped off her father's lap and pranced off.
'That girl...!' Sawada Iemitsu sputtered out in shock. 'Are you OK, Nono?!'
'I-I'm alright...' Timoteo Vongola wheezed out from pain, clutching his broken arm gingerly. 'Its just natural. Her own intuition sensed danger coming to her and she retaliated. But I never expected it to awaken so soon as she sensed our intent to seal her flames away. It looks like she won't be happy with us for a while.'
'Nevermind that, we need the hospital now!'
Since that day, Tsunami pretended her father didn't exist and stayed with her mother, or by herself to his dismay.
He tried on family outings, but Tsunami would make sure her mother is in the middle, not her.
Thus Iemitsu's final year with his family, was a sad one because Tsunami never forgave them for it and as far as the girl is concerned, she no longer has a father.