The Ultimate mode that allows each character to be used only once before becoming unavailable is Smashdown. It is a multiplayer mode designed to make players adapt quickly rather than repeatedly selecting their strongest or most familiar fighter.
After a character is chosen in Smashdown, that fighter cannot be selected again in the following rounds of the same session. This gradually shrinks the available roster and encourages players to explore unfamiliar matchups, mechanics, and play styles.
Smashdown is distinct from Squad Strike, where each player assembles a team of three or five characters for a single extended contest. Classic Mode is a traditional progression of battles, while Tourney organizes matches into a tournament bracket. The one-use character rule is therefore the defining feature of Smashdown.