Near the end of the True Pacifist route, Toriel arrives at "New Home" (The Monsters' Capital) and saves the human from Asgore. However, Flowey appears and absorbs her soul along with all the other monsters in the Underground to regain his true form, Asriel.

Does Toriel save you from Asgore?

Toriel cares for humans who fall into the Ruins and the protagonist is no exception. She tries to keep the protagonist in the Ruins, as Asgore killed the other humans who left her care. If the protagonist spares her, she lets them leave the Ruins, but not before giving them a parting hug.

Do you have to kill Asgore in pacifist?

Pacifist Boss Tips: King Asgore

You must fight King Asgore. Make sure you are loaded with healing items and have your strongest weapon and armor equipped. This battle will be very, very difficult if you have stuck to the Pacifist checklist. Make sure you have your Butterscotch Pie in your inventory for this battle.