I just noticed that the soul that kris is removing during the ending is positioned above the circle of deltarune, would that mean that the red soul (the player) is the angel? :
No pain without gain! — Just a bit of theory about Kris
Dream or Reality — Why do you put your soul in a cage?
Heart in a Cage -deltarune- by kiacii-official on DeviantArt
image: kris from deltarune, wandering about with their SOUL in their birdcage wagon and a knife in hand. their fac… | Undertale, Undertale art, Favorite character
Deltarune's Undertale 2 Bait-and-Switch is a Superb Piece of Video Game Writing | USgamer
The Unsettling "Pacifist" World of Deltarune — Rhiannon Thomas