In "Harry Potter", Voldemort did not kill Myrtle. Myrtle was not killed by Voldemort, but by the basilisk in the Chamber of Secrets.
In 1943, when Myrtle was a student at Hogwarts Ravenclaw House, she was killed by a basilisk in the Chamber of Secrets. At that time, she couldn't stand Olive Humbe's cynicism and hid in the women's bathroom to cry. Then she heard someone coming in and heard them whispering. She recognized that it was a boy's voice, so she opened the door to remind her that this was the women's bathroom, but she was bumped into by a basilisk.
Myrtle, who became a ghost, chased Olive Humbey and kept harassing her, trying to make her pay for having laughed at her. She had to stop until the Ministry of Magic intervened. So Myrtle ended up back in the girls' bathroom, where she cried and cried whenever she was in pain, getting water everywhere.
Origin of Voldemort's name
Voldemort's original name is Tom Marvolo Riddle, where "Tom" comes from his father, Tom Riddle Sr., and his middle name is "Marvolo" ” Derived from his maternal grandfather, Marvolo Gaunt.
His name "Voldemort" comes from the French Vol de Mort. "Voler" means "flying, stealing", "vol" is its noun form; "de" is a preposition, equivalent to "of" in English; "mort" means death, so there is "fly" It means "away from death" or "stealing death".
A few years after starting his studies at Hogwarts School of Witchcraft and Wizardry, Tom began to use the name "Voldemort" (Chapter 17 of "Harry Potter and the Chamber of Secrets" Tom mentioned that only the closest friends know).