Pokemon Sun & Moon
Pokemon Sun & Moon
Alolan forms were introduced by the developers in order to illustrate that Pokemon are living, changing creatures. Pokemon who had migrated to the Alola region would therefore follow a different evolutionary path than their original counterparts, similar to the way real animal species in the Galapagos Islands followed their own unique evolutionary paths.

In order to create these Alolan forms, the developers revisited the Pokemon that originally appeared in Pokemon Red & Blue, since they are widely recognized by long time fans and would best express this concept with them. It would also help commemorate the 20th anniversary of the Pokemon series as a special surprise for fans.
Contributed by SkyminHAZBOZ
Pokemon Sun & Moon was Shigeru Ohmori's first time as the director of a new generation of Pokemon games. Because the game commemorates the 20th Anniversary of Pokemon, he wanted to go back and look at what he thought Pokemon games should be and create his own take on the series. He came up with the idea of Trials & Totem Pokemon as a replacement for Pokemon gyms to tie in with the Alola region's theme of powerful and abundant nature. He thought it would be an interesting concept and a way to make the game feel fresh for both veterans of the series and newcomers alike.
Contributed by SkyminHAZBOZ
The time difference between the versions was inspired by the idea that Pokemon are living creatures - some are active during the day, others are active during the night. The developers thought this would be a useful feature to facilitate more communication and trading amongst friends.
Contributed by SkyminHAZBOZ
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Ash-Greninja was added to the games to encourage fans of the Pokemon anime series and especially kids to try out the special demo version (which Ash-Greninja appears in a special Pokemon that is able to be transferred to the full game), as it was a popular character among them.
Contributed by SkyminHAZBOZ
To help commemorate the 20th anniversary of the Pokemon series, the developers wanted to look at trainers and Pokemon as living things and express that in a better way. When coming up with ideas for Pokemon Sun & Moon, they created a theme for the game based around the concept of life, with both the sun & moon both being important to all life on earth. A place that came to mind to reflect this was Hawaii, an area with lots of sunshine, clear nights, and an abundance of life.
Contributed by SkyminHAZBOZ
Z-Moves were introduced in order to have something that would allow players to use a wider variety of Pokemon in battle.
Rather than have an individual Pokemon that players can focus on and make strong like with Mega Evolutions in Pokemon X & Y, Z-Moves were designed as a system where any Pokemon can use them and be stronger and more relevant in battle.
Contributed by SkyminHAZBOZ
Raichu's Alolan form is a reference to the Surfing Pikachu seen in many Pokemon releases ranging from games to merchandise. More Specifically, Alolan Raichu seems to be based on surfing Raichus from Pokemon Stadium. This Raichu is surfing on its tail and even has the ability "Surge Surfer" and the special Z-Move "Stoked Sparksurfer".
Contributed by Mass Distraction
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Marowak's Alolan form with its new Ghost typing is most likely a reference to the non-playable ghost of Marowak found in Lavender Town's Pokemon Tower all the way back in Pokemon Red, Blue, Green, Yellow, Fire Red and Leaf Green.
Contributed by Mass Distraction
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After the killing of Harambe in the Cincinnati Zoo, many upset fans wanted Harambe to be added to the Pokedex in Pokémon Sun and Moon. Fans created a change.org petition outlining their wish, and the petition went on to gain over 120,000 signatures. Despite the amount of support, there has been no official comment from anyone affiliated with the Pokemon brand.
Contributed by EpicNoah15
According to information for the Greninja obtained at the beginning of the game's pre-release demo, the name of its original trainer is 'Ash'. This Greninja also met Ash on October 17, 2013, the exact date the first episode of the Pokemon XY Anime was broadcast in Japan. In the episode, Ash Ketchum met Greninja as Froakie.
Contributed by MeleeWaluigi