Gandalf’s reference is the character from The Lord of the Rings fictional universe

The Lord of the Rings is a series of three epic fantasy adventure films directed by Peter Jackson, based on the novel written by J. R. R. Tolkien. Set in the fictional world of Middle-earth, the films follow the hobbit Frodo Baggins as he and the Fellowship embark on a quest to destroy the One Ring, to ensure the destruction of its maker, the Dark Lord Sauron.

Gandalf the Grey, later known as Gandalf the White, and originally named Olorin (Quenya; IPA: [oˈloːrin]), is one of the main characters in J.R.R. Tolkien's The Lord of the Rings and The Hobbit. In these books, Gandalf is portrayed as a wise, powerful wizard, a member of the Council of the Wise, who helps the weak.

By nature, comes from the race of Ainur and is counted among the small (in power) angelic spirits - the Maiar. Gandalf was considered one of the wisest Maiar. His mission was to help the free peoples of Middle-earth to fight the Dark Lord Sauron, who was also one of the Maiar but had turned to evil. Gandalf, the only one sent by Istari, succeeded in his mission.

Gandalf wields the Ring of Fire Narya, one of the Three Elf Rings, and most of his magical powers are related to fire and light. He says of himself, "...I am a servant of the Secret Fire, wielder of the Flame of Anor...You shall not pass"