Chaos vs. Order

Chaos vs. Order, also known as Final Fest: Splatocalypse, was a Splatfest event in Splatoon 2. It was held in all regions for 72 hours from 2019-07-18 to 2019-07-21, and for the first time, all regions began and ended at the same time. It was announced at the Splatoon 2 World Championship 2019 and on social media on 2019-06-08. It was announced in-game on 2019-06-26. The results were given on 2019-07-21.

Trailer
https://www.youtube.com/watch?v=PEk-Ib0n2Uc

Details
This Splatfest was meant to be the final Splatfest held in Splatoon 2. In this Splatfest, a new Shifty Station layout was introduced, alongside the return of every Shifty Station layout introduced prior. For the first 48 hours, all previous layouts were part of the Splatfest Battle rotation, with two different Shifty Stations joining the other standard stages. For the last 24 hours, only the new layout, MC.Princess Diaries, was used in the rotation. Also, the chance to encounter a 100× Battle was 100× more likely for this Splatfest.

During the Splatfest, Inkopolis Square took on a different appearance. The sky appeared post-apocalyptic. The Galleria displayed tattered flags for Team Chaos, with barbed wire wrapped around the outside. On the other side, The Shoal and Inkopolis News Studio were painted white, and displayed the flag for Team Order along with power lines wrapping around the outside.

Four pieces of headgear (two for each team) were available in a Squid Research Lab Report article on Nintendo Switch News.

A trailer revealed the team alignment of characters and weapons, detailed in the table below.

Shifty Station's outcome
Although this was intended to be the final Splatfest, Nintendo announced that Version of Splatoon 2, which went live after this Splatfest ended, introduced Splatfest Battles to Private Battle mode. Every Shifty Station layout, including MC.Princess Diaries, is available in this mode and the host can choose the team ink colors from a list of all 51 Splatfest color schemes from every region. Every stage, including the regular stages available in the base game, also has a day and night mode.

Music
This Splatfest included unique battle music tracks that did not play in any other Splatfest. The normal Splatfest battle opening theme was replaced by the minor-key version that played during the opening of the Octo Expansion's Turf War, except ending much sooner.

In day one, Ink Me Up returned from, with the Squid Sisters' version of Now or Never! playing if chosen, while Shark Bytes made its debut as a battle theme. In day two, Spicy Calamari Inkantation debuted, being the only song playing, albeit with its intro mostly removed. There was also a unique version of Now or Never! based on Off the Hook's version, co-starring the Squid Sisters. In day three, Fly Octo Fly ~ Ebb & Flow (Octo) debuted as a battle theme, being the only one available and notably replacing Now or Never! at the one-minute mark.

Trivia

 * In the promotional art, Callie is shown wearing Pearl's crown from the Octo Expansion while Marie wears Marina's headphones.
 * It is widely suspected that the outcome of Chaos vs. Order will affect the plot of a sequel game, similarly to Callie vs. Marie.
 * Every character in the game who leads a major role chose a team, including the antagonists - the Octarians, DJ Octavio, the Salmonids and the Telephone.
 * The Telephone is of particular note, as although it was destroyed in the Octo Expansion, it is shown still in one piece in the promotional art.
 * In Germany, this Splatfest shares its team titles with an earlier one from, Messy vs. Tidy. However, the latter's longer team titles that were used in the announcement (Unordentlich vs. Ordentlich) make it clearer that they are about neatness.
 * While the Splatfest had already announced by Nintendo at the time, it was foreshadowed in-game by both victory dialogues for Unicorn vs. Narwhal. Like in Splatoon, this foreshadowing was only present in the dialogue for North America's Splatfest.
 * In the announcement dialogue, Pearl mentions Agent 8 and Cap'n Cuttlefish, making this the only Splatfest to have been confirmed to take place after the Octo Expansion.
 * When the Splatfest was announced in-game, Pearl invoked Article 4 of Splatfest Law, in which the outcome of the Splatfest must take effect in Inkopolis, hinting at a major change in the future.
 * A similar rule stating that what the winning side prefers is legally better than what the losing team wants has also been referenced during previous Splatfest dialogue, including Cake vs. Ice Cream, Film vs. Book, Chicken vs. Egg, and Front Roll vs. Back Roll (indirectly). However, it has never been referred to as Article 4; all other references have been to "Chapter 3" instead, implying that Article 4 may be a separate part of Splatfest Law altogether.
 * A few lines through the announcement dialogue, the normal background music is temporarily replaced by The Plan.
 * Both Pearl and Marina's new outfits' color schemes are similar to that of their Trick vs. Treat ones, with Pearl's being mainly black and gold, and Marina's being mainly white and silver.
 * In the days leading up to Splatfest, gold and silver stickers started to show up and quickly spread around the square. All these stickers featured images drawn by the community.
 * Interestingly, an image drawn for Team Order could appear on a Team Chaos and Team Order sticker, and vice versa.
 * In Recon mode, Wayslide Cool, The Secret of S.P.L.A.T., Windmill House on the Pearlie, Goosponge, and The Bouncey Twins all lacked the ambience that plays in the other Shifty Stations. The Bouncey Twins had lacked the ambience before in its original Splatfests (Retro vs. Modern and Tsubuan vs. Koshian).

English
Announcement

Results

Results if Order were to win

Dutch
Announcement

Results

Results if Order were to win

French (France)
Announcement

Results

Results if Order were to win

French (Canada)
Announcement

Results

Results if Order were to win

German
Announcement

Results

Results if Order were to win

Italian
Announcement

Results

Results if Order were to win

Japanese
Announcement

Results

Results if Order were to win

Russian
Announcement

Results

Results if Order were to win

Spanish (Spain)
Announcement

Results

Results if Order were to win

Spanish (Latin America)
Announcement

Results

Results if Order were to win