Grims (plural, Grim), are an ancient and powerful species of Dark Realm denizens that are comparable to Demons and capable of wielding a Keyblade, although they are preserved and enhanced by the power of Darkness they are ensured greater endurance via having human bodies - similar to Higher Nobodies while a trait unshared by either Heartless or Unversed, the Grims were believed to have gone extinct during the Keyblade War.
Grims were as powerful as durable as any Somebody but had a natural affinity for the power of Darkness and could wield a Keyblade (often a Keyblade of the Realm of Darkness) without fear of the Heartless attacking them, in actuality Grims could even control Heartless and/or Nobodies, something that most Somebodies would be incapable of doing or without having to look over their shoulders for every internal threat from their followers.
When Somebodies are made into Grims, they retain their natural appearance and all that changes are their capacity in using the power of Darkness, however their eyes may glow a yellow colour from time-to-time but is highly dependent on the type of person and the amount of Darkness they use on a day-to-day notice.
Like all things tainted with Darkness, the Grims can enhance their durability, strength, speed and magical capabilities, they also have a repressed aging speed. All these traits become stronger the older (chronologically) that the Grim becomes.
- In Fairy myths, Grims are spirits of Black Dogs that guard Burial zones.