As surprised as Willow is with Vamp Willow, she feels bound to her, and does not have the heart to allow Buffy to kill her. Both Willows make the observation that "this world's no fun", before they send Vamp Willow back into the alternate dimension from which she came, whereupon she is staked and dies immediately.

Is Willow in season 7 of Buffy?

Willow appears in the Angel episode "Orpheus" to re-ensoul Angel (David Boreanaz) as she previously did before in "Becoming". After successfully re-ensouling Angel, she brings Faith (Eliza Dushku) back with her to Sunnydale to help in the fight against The First Evil.

How does Buffy stop Willow?

Overwhelmed by her pain and all the pain she senses, she announces she will end it by ending the world. Buffy manages to partially block Willow's attack, but she and Dawn are thrown underground while Xander is knocked unconscious.