At least some content in this article is derived from information featured in Harry Potter: Hogwarts Mystery. Spoilers will be present within the article.
At the end of the 1984–1985 school year, after Jacob's sibling fought the cursed ice, they noticed some code written on the wall. Rowan Khanna deciphered the code, which suggested there was an Ice Knight who stood guard past the Vanished Stairs.
At the end of the 1985–1986 school year, when Jacob's sibling, Bill Weasley and another student eventually found and opened the Vault of Ice, the Ice Knight immediately attacked them, freezing two of the students. Jacob's sibling was eventually able to defeat it using offensive spells.
During the 1988–1989 school year, Jacob's sibling returned with Bill when they were completing Sir Cadogan's agenda, initiating a second duel with the Ice Knight, who had been revived by Madam Rakepick, and was defeated a second time.
- Harry Potter: Hogwarts Mystery (First appearance)