First, do you play the all-ages version? Gotta ask this since the collab is only for the all-ages version, no 18+ version. And it seems like you need to play both games to get the character. Idk how the events are structured at the other game, so your guess is as good as mine. If this character is released in the same way as Moldevort was, we will get another chance to get her in the future. Molde was part of a collab too and was released in a gold rush one year later.