Undyne

Core Preta Is The Captain of the Royal Guard In Buddytale

Normal
Core prepares to throw her spear at the protagonist.

Cor debuts in armor varying in light and dark shades of gray, but without armor, She wears a Dark Pink and Dark Purple tanktop and Blue jeans.

Blue-Erry's Reunion
During the Reunion with Blue-Erry, Core wears a white turtleneck under a black leather jacket, pants, and lets some of her hair down.

Undead
Whenever she persists through Determination after her HP reduces to zero, her Pastel blue pupils turn white, and her white turns black.Her Left eye socket emits a flashing light. Her hair spikes at the ends and her fins become more rigid and pointy. She also appears to have donned a new set of darker colored armour with souls/hearts on her chestplate and on her new white gloves, accompanied by boots with pointed toes.

Blue-Erry
Core is Blue-Erry's sister which flurishes into a full Reconciliation on a pacifist run.

UndertaleTrash3
She is Trash's friend and trainer. She also teaches cooking despite sucking at it herself.

Sakura's little sister
Core is Saku's boss, she never refers to Her by name.

Corly
Corly idolises Core