At least some content in this article is derived from information featured in Harry Potter: Hogwarts Mystery. Spoilers will be present within the article.
Death and post-mortem
He died in 1882, at the age of 79. By the early 1990s, he was featured on a Chocolate Frog Card. His card was one of the first in Harry Potter's collection, being among the ones he obtained on his trip to Hogwarts School of Witchcraft and Wizardry in 1991.
Grunnion's name could possibly be in recognition of Alberich, a powerful wizard from "Song of the Nibelungen." The poem is mythical, but was the basis for Wagner's Ring Cycle. In Wagner's version, Alberich makes a ring from gold that he has found and places a curse on it against its thief. Interestingly, one of the prizes given to a 'hero' of the Ring Cycle is an Invisibility cloak.
- Harry Potter and the Philosopher's Stone (Mentioned only)
- Harry Potter and the Philosopher's Stone (video game) (Appears on a Famous Wizard Card)
- Harry Potter and the Chamber of Secrets (video game) (Appears on a Famous Wizard Card)
- Pottermore (Appears on a Famous Wizard Card)
- Harry Potter: Hogwarts Mystery (Mentioned only)