The Ultimate Choice

"It's the super-ultra-final-omega battle! Make the ultimate choice with Soul Melter!!"

- The Ultimate Choice on Soul Melter

The Ultimate Choice is a sub-game in Kirby Star Allies similar in concept to The Arena sub-games from previous games in the Kirby series. This one is different to The Arena sub-games, as the player can select the difficulty. Although five difficulties are available by default, there are three extra difficulties which can be unlocked. Completing Guest Star ???? Star Allies Go! once and completing The Ultimate Choice once unlocks Fiery Showdown and Infernal Crisis difficulties, and completing The Ultimate Choice once on Fiery Showdown or Infernal Crisis unlocks the Soul Melter difficulty.

Gameplay
The player can select Kirby without an ability, a Copy Ability, or a Dream Friend; pressing X when selecting a Copy Ability will allow the player to become the Friend instead. The player can also add up to three more friends, which can be controlled by other players or CPUs. Before starting and after every round, Kirby and his friends will be taken to the rest area, with six Maxim Tomatoes that get replaced by regular tomatoes when used. On higher difficulties, some of the Maxim Tomatoes get replaced with Pep Brews, one for each extra difficulty level, culminating six Pep Brews at Infernal Crisis. Treasure chests containing Picture Pieces appear after defeating a boss.

If playing on the Soul Melter difficulty, all healing items will be replaced by regular tomatoes, and if playing on any of the last three difficulties, maximum stamina is reduced, even more so at the Soul Melter difficulty. The player can still use amiibo to get picture pieces and food items in the rest area or during battles (except when they are on the Star Allies Sparkler). However, like in Kirby: Planet Robobot, using amiibo functionality even once will put the amiibo insignia next to the player's clear score after completing The Ultimate Choice.

The higher the difficulty level, the more points are awarded for clearing The Ultimate Choice.

Battles
Depending on the difficulty, what bosses will be faced and how many bosses are fought will vary. All bosses are fought in the same order on each difficulty setting and each difficulty adds more bosses onto the order. This linear concept carried over from Kirby: Planet Robobot. The rest area starts out in a beige room similar to the Dream Palace, but as the difficulty rises it can eventually transition into a fiery, darker setpiece.

Sweet Breeze

 * 1) Whispy Woods
 * 2) Mid-Boss All Stars #1 (Bonkers, Puppet Dee, Mr. Frosty)
 * 3) King Dedede
 * 4) Meta Knight

Mild Stroll

 * 1) Whispy Woods
 * 2) King Dedede
 * 3) Mid-Boss All Stars #2 (Chef Kawasaki, 2 Anger Maskers, Bugzzy)
 * 4) Pon & Con
 * 5) Kracko and Twin Kracko
 * 6) Meta Knight

Zesty Expedition

 * 1) Whispy Woods
 * 2) King Dedede
 * 3) Mid-Boss All Stars #2 (Chef Kawasaki, 2 Anger Maskers, Vividria, Bugzzy)
 * 4) Meta Knight
 * 5) Pon & Con
 * 6) Kracko and Twin Kracko
 * 7) Francisca

Spicy Adventure

 * 1) Whispy Woods
 * 2) Mid-Boss All Stars #1 (Bonkers, Puppet Dee, Mr. Frosty)
 * 3) King Dedede
 * 4) Mid-Boss All Stars #2 (Chef Kawasaki, 2 Anger Maskers, Vividria, Bugzzy)
 * 5) Meta Knight
 * 6) Pon & Con
 * 7) Kracko and Twin Kracko
 * 8) Flamberge

Sizzling Threat

 * 1) Whispy Woods
 * 2) Mid-Boss All Stars #1 (Bonkers, Puppet Dee, Mr. Frosty)
 * 3) King Dedede
 * 4) Mid-Boss All Stars #2 (Chef Kawasaki, 2 Anger Maskers, Vividria, Bugzzy)
 * 5) Meta Knight
 * 6) Pon & Con
 * 7) Kracko and Twin Kracko
 * 8) Zan Partizanne
 * 9) Hyness

Fiery Showdown

 * 1) Yggy Woods
 * 2) Mid-Boss All Stars #1 (Bonkers, 2 Shield Carriers, Twin Frosty)
 * 3) King Dedede
 * 4) Mid-Boss All Stars #2 (Bugzzy, Chef Kawasaki, 2 Float Slimes, Twin Vividria)
 * 5) Meta Knight
 * 6) Goldon & Silvox
 * 7) Kracko and Twin Kracko
 * 8) Francisca
 * 9) Hyness
 * 10) Morpho Knight

Infernal Crisis

 * 1) Yggy Woods
 * 2) Mid-Boss All Stars #1 (Bonkers, 2 Shield Carriers, Twin Frosty)
 * 3) King Dedede
 * 4) Mid-Boss All Stars #2 (Bugzzy, Chef Kawasaki, 2 Float Slimes, Twin Vividria)
 * 5) Meta Knight
 * 6) Goldon & Silvox
 * 7) Kracko and Twin Kracko
 * 8) Francisca
 * 9) Flamberge
 * 10) Zan Partizanne
 * 11) Hyness
 * 12) Morpho Knight
 * 13) Void Termina

Soul Melter

 * 1) Yggy Woods
 * 2) Mid-Boss All Stars #1 (Bonkers, 2 Shield Carriers, Twin Frosty)
 * 3) King Dedede
 * 4) Mid-Boss All Stars #2 (Bugzzy, Chef Kawasaki, 2 Float Slimes, Twin Vividria)
 * 5) Meta Knight
 * 6) Goldon & Silvox
 * 7) Kracko and Twin Kracko
 * 8) Francisca
 * 9) Flamberge
 * 10) Zan Partizanne
 * 11) Hyness
 * 12) Morpho Knight
 * 13) Void Termina and Void Soul

Related Quotes
"Consume all in Sweet Breeze/Mild Stroll! Bon appétit!"

- Flavor Text

"Power up and polish off Zesty Expedition/Spicy Adventure/Sizzling Threat!"

- Flavor Text

"Give it your all! Challenge yourself with Fiery Showdown/Infernal Crisis!"

- Flavor Text

"It's the super-ultra-final-omega battle! Make the ultimate choice with Soul Melter!!"

- Flavor Text

Trivia

 * The illustration of Kirby pouring hot sauce is reminiscent of the plot in "The Hot Shot Chef / A Spice Odyssey" from Kirby: Right Back at Ya!
 * The face Kirby makes while highlighting the Soul Melter difficulty is a reference to the Kirby: Right Back at Ya! episode Frog Wild, where it matches the possessed Kirby's expression.
 * Grand Mam is the only boss that appears in Story Mode that does not also appear in The Ultimate Choice.
 * The hot sauce has the Jambastion symbol on it.
 * Before unlocking Soul Melter, the color scheme of the sub-game's logo is primarily red. After unlocking it, it changes to primarily black.
 * On Soul Melter difficulty, certain boss themes are replaced by other themes from the series:
 * King Dedede's theme becomes "History of Dedede" from Kirby Fighters Deluxe.
 * Meta Knight's theme becomes "Battle with the Spirit of Self" from Kirby: Planet Robobot.
 * Goldon and Silvox's theme becomes "Decisive Battlefield" from Team Kirby Clash Deluxe.
 * Kracko and Twin Kracko's themes become "Ordeal! (Orchestral)" and "Ordeal! (Electric)" from Team Kirby Clash Deluxe, respectively.
 * After clearing The Ultimate Choice, a message, which varies depending on the difficulty chosen, will appear proclaiming the player's victory:
 * Sweet Breeze through Sizzling Threat: Victory!
 * Fiery Showdown through Infernal Crisis: Huge Victory!!
 * Soul Melter: Incredible Victory!!!
 * Through Sweet Breeze to Infernal Crisis, the fanfare that plays in the victory screen is a snippet of Friendly Field's background music. On Soul Melter, this fanfare is replaced with a snippet of Green Greens' theme.
 * The "intensity gauge" setup of The Ultimate Choice is very similar to the custom difficulty modifier systems in Kid Icarus: Uprising and Super Smash Bros. for 3DS & Wii U. It further mimics these games by showing increasingly infernal and more threatening visuals on the difficulty selection menu as the level is increased, with the hardest option appearing completely demonic. In this way, Kirby Star Allies can be considered the first Kirby series game to show distinct influence from games directed by Masahiro Sakurai that were made after his departure from HAL Laboratory.