He's back. He's been back for a while now. And Ginny can't get over it, that after everything, it only took him a few more years than if she'd just gone and died. He exists, and people are dying, and he's not 'Tom' to her anymore. Now he'll be 'Voldemort' because that is a monster's name and he is a monster.
Voldemort,
You've come back. Has this letter reached you? Do you know who I am? I'm the girl your diary tried to kill. I'm still alive, but your book is dead, with a hole through it from a basilisk's fang. I used to hate you. Now I hate you even more. You'll be defeated in the end. Ha!
Mockingly
Ginny W.