Jack makes his debut as a demon on the overworld map outside Bael's Castle.
If Nakajima picked up a Member's Card from Rag's Jewelry, and the player continues on to MTII after defeating Lucifer, a Member's Card will be given to the hero by a kid in the shelter.
Jack Frost Jr will ask the hero if he knows his parents; by responding "Yes", ћ3000, 3000 MAG, and 10,000 EXP will be received.
Later, after passing through Mammon's Gate and reaching the Island of Dreams, Jack O' Lantern can be encountered; after talking to him, the player can go to a treasure chest room and meet Jack Frost Jr. After reaching Bael's Castle, the Fallen Angel Wing cloak can be acquired as the Code Breaker Grand Prize; with this and the Heidrun in possession, Jack Frost Sr.
will be encountered upon entering the Cathedral of Shadows; he will give the hero a Qing Long, Bai Long, and Kali.
After MTII is finished, Jack Frost Momma can be encountered by going to see the nurse in the shelter.
In the Third Kalpa, Black Frost appeared in a room with two 'switches' after Dante was defeated.
After talking to Black Frost, he joined the Demi-Fiend's party without his consent, believing that he could grow stronger still by joining the one who defeated him.
Normal Jack Frosts can be encountered and contracted in Ginza.
Jack Frost is a sprite of English folklore that only appears in wintertime.
She will introduce the hero to the secret Deities - Zeus, Leto, Artemis, and Apollo - and give hints as to where they can be found.