Fimbultyr is the fifth and final War God in Gungnir, and the only one that can be missed out on if the criteria for it are not met by Scene 25; the player must be on the A+ Ending path, which involves fielding Alissa in every single battle since recruitment, never letting her die, and picking choices throughout the game that are favorable to her.

When summoned, Fimbultyr bestows the Brave status effect upon all targets, permitting them to move and act without accruing Wait time.