The Nightopians (sometimes referred to as "Pians") are residents of the Night Dimension and minor characters in the NiGHTS series. They are fairy-like creatures who inhabit the visitor's dreams. The Nightopians are considered to be the series' mascots.
The Nightopians are fairy-like creatures who are minor characters in the NiGHTS series. They don't have any goal other than having fun, and don't hold any significance to the game's story. Their Artificial Life is a special feature in the games.
During gameplay, the Nightopians are spread throughout the levels, where they'll just try to find ways of having fun and reproduce by dropping eggs around. If a Nightopian comes close to a Nightmaren, the Nightmaren will try to eat it. In both NiGHTS into Dreams and Christmas NiGHTS, the Nightopians have exclusive behaviors for each level; for example, in Soft Museum, the Nightopians may sculpt silver statues of NiGHTS and in Stick Canyon, the Nightopians can be seen using jackhammers.
The player can change the Nightopians mood by making them happy, sad, scared or angry, depending on how NiGHTS treats them. Everytime the player beats a level and defeats the boss, the Nightopians mood will update depending on how NiGHTS treated them. In NiGHTS into Dreams, the levels music will change depending on the Nightopians mood.
Opening eggs in front of Nightopians or attacking Nightmarens will make the Nightopians happy. When replaying the levels, they'll see NiGHTS as a friend and wave at them. They will also start breeding with each other more frequently and may cause superpopulation in the level.
Drill dashing into a Nightopian will make them fear NiGHTS. When replaying the level, they'll run away scared of NiGHTS. Paralooping a Nightopian in NiGHTS into Dreams and Christmas NiGHTS into Dreams will kill it, making the other Nightopians sad, scared or angry at NiGHTS.
In Christmas NiGHTS into Dreams and in the remasters of NiGHTS into Dreams released for PlayStation 2, PlayStation 3, Xbox 360 and PC, there's an unlockable feature known as the Nightopian Collection where the player can view their Nightopian information stored in a saved game file.
In every game, the Nightopians start disappearing after a while, starting from the oldest ones.
See main Article: MyDream/Nightopian Garden
In NiGHTS: Journey of Dreams, there's a feature called My Dream (Also known as Nightopian Garden). Unlike in the previous games, paralooping a Nightopian in this game won't kill it, instead, it will teleport the Nightopian to a garden where the player can take care of them. The player can also teleport Nightmarens and take care of them as well as feed them with Nightopians.
See main Article: Mepians
The Mepians are a special type of Nightopian. They are Nightopians with Nightmaren body parts. When NiGHTS attacks a Nightmaren, the latter will turn into an orb, and if the orb collides with a Nightopian, an egg will appear. When NiGHTS opens it, a Nightopian with Nightmaren body parts will be born.
A Mepian can be born with one to four Nightmaren body parts, these are the Nightmaren's head, torso (wings come with it), arms and legs. Hitting a Mepian with a different Nighmaren will make another Mepian that will have parts of both the hitten Mepian and the Nightmaren.
Much like the regular Nightopians, NiGHTS behavior will affect the Mepians mood, so the Mepians may befriend NiGHTS or hate them.
Unlike the regular Nightopians though, who always care about others of their kind, a Mepian may be nice or may be mean towards regular Nightopians and other Mepians. Some Mepians can be aggressive towards other Nightopians and other Mepians but at the same time, they can befriend NiGHTS.
The Mepians behavior will also affect the Nightopians mood, so if Mepians are mean towards them, the Nightopians' mood will get lower. Much like a regular Nightopian, the Mepians are Nightmarens prey. They also disappear after a while.
Making a Mepian in the NiGHTS into Dreams HD remaster for the PlayStation 3, Xbox 360 and PC unlocks the Hello Mepian Trophy.
Examples of Mepians:
See main Article: King Pian
The King Pian (or Super Pian) is a rare type of Nightopian. As the name suggests, he is the king of all the Nightopians. When he appears, the King Pian will build a castle in the level and attack the Nightmarens by throwing rocks at them. If the Mepians are too aggressive towards Nightopians, the King Pian will see them as a thread too and will attack these Mepians until NiGHTS kills them with the paraloop. Much like the Nightopians and Mepians, the King Pian also disappears after a while. However, it takes much longer. The castle he builds is permanently added to the level though.
In NiGHTS into Dreams and Christmas NiGHTS, the King Pian wears red royal clothes and has a small tiara-like crown with a red jewel, he is also the size of a regular Nightopian. In Journey of Dreams, he looks like a regular Nightopian but bigger, he wears a cape and has a much bigger golden crown.
A King Pian is born when two Mepians, each with a single Nightmaren body part, breed. However, the Mepians can't have the same Nightmaren body parts (example: if one Mepian has a Nightmaren head, the other can't). To make the Mepians breed, it is necessary to make them happy. The player can do that by defeating Nightmarens in the levels, avoiding drill dash near the Nightopians and Mepians and of course, the player shall not paraloop the Nightopians and Mepians.
It should be noted that the chances of getting a King Pian are random, which means that breeding two different Mepians created from two different Nightmarens may simply result into another Mepian. The chances of getting a King Pian egg are 1 out of 4.
One of the Power Panels which appeared in both NiGHTS into Dreams and Journey of Dreams called Nightopian Helper makes a Nightopian spawn. The Nightopian will follow NiGHTS and give them a magnet effect for a limited time.
The Runaway Nightopian
According to the NiGHTS into Dreams manual, it was a Nightopian who found Elliot and Claris and introduced NiGHTS to them. However, that is never shown on screen. This particular Nightopian is also never seen in the game.
Weirdly, according to the game's manual, the Nightopian is said to have escaped from the dream world to go after Elliot and Claris. This contradicts with the game, where it's Elliot and Claris who are seeing going to the dream world after running away from the Nightmarens.
In the NiGHTS Archie Comics, two Nightopians called Napp and Snuze help NiGHTS after the latter starts their uprising. Snuze also has a similar role to this particular Nightopian, as it goes to the waking world, meets up with Elliot, explains to him NiGHTS situation and leads him to NiGHTS. In NiGHTS: Journey of Dreams, Owl has a similar role.
Star Sign Nightopian
In both NiGHTS into Dreams and Christmas NiGHTS, there's a Nightopian who stays above the Ideya Palace, showing how many stars (bells in Christmas NiGHTS) the player has collected. Bumping into this Nightopian in the fourth lap will reward the player with 10 points for each star they collected. However, it should be noted that this Nightopian will run away if the player kills a Nightopian with the paraloop before bumping into it. The Nightopian won't run away if the player kills a Mepian, though.
- Christmas NiGHTS into Dreams: Nightopians appear in Christmas NiGHTS into Dreams, where they have the same function as in the main games, except this time, they are wearing Christmas outfits. Additionally, the Nightopians may sing Christmas songs, on rare occasions, in the month of December.
- NiGHTS: Flying Through the Sky Without Wings: In the NiGHTS Storybook, Nightopians make minor appearances. First, they watch NiGHTS playing their flute, then later, they appear getting attacked by Nightmarens, and lastly, they appear after NiGHTS and Elliot save Nightopia from the Nightmarens.
- NiGHTS into Dreams (LCD): The Nightopians appear in the LCD adaptation of NiGHTS into Dreams, where they retain the player's health bar energy. In this game, the Nightopians are called "fairies".
- NiGHTS into Dreams Archie Comics: Nightopians make minor appearances in the NiGHTS Archie Comics series. Two Nightopians called Napp and Snuze are major characters who helped NiGHTS after they started their uprising.
- NiGHTS Dream Wheel: A Nightopian makes a small appearance in the NiGHTS-themed slot machine, NiGHTS Dream Wheel, in the game's roulette.
- Game Gag 1P Comic Sega-hen: Nightopians are one of the many NiGHTS characters to make a small appearance in the manga.
- Sonic Adventure and Sonic Adventure DX: A Nightopian made a cameo in Sonic Adventure and Sonic Adventure DX as a card in the NiGHTS thematic pinball table from Casinopolis.
- Shenmue: A Nightopian appears in Shenmue as a capsule toy along with a Chao from the Sonic series.
- ChuChu Rocket!: The Nightopians are an unlockable skin for the ChuChus. To unlock them, the player must beat all of the 50 courses from the game.
- Phantasy Star Online and Billy Hatcher and the Giant Egg: In Phantasy Star Online, the Nightopians (referred to as "Pian" in the game) appear as a a Mag, an equippable creature that contributes bonuses to that player's stats. Both Phantasy Star Online and Billy Hatcher also feature an 8-bit NiGHTS into Dreams mini game called NiGHTS ~ Score Attack ~, where the player controls NiGHTS through Spring Valley. NiGHTS must collect a certain amount of Blue Chips and/or rings, then return to the Ideya Palace. Although the Nightopians don't appear during gameplay segments, they do make a cameo in the game's tittle screen.
- Sonic Pinball Party: Nightopians appear in all of the NiGHTS thematic pinball tables in the game.
- Sonic Riders: Two tiny Nightopians can be seen in the Sega Carnival circuit from Sonic Riders, when the racers are rolling around the Twin Seeds tower.
- Sega Superstars Tennis: Nightopians appear during NiGHTS' All-Star Move and at the NiGHTS tennis court.
- Phantasy Star Portable 2: There's a Nightopian costume for the playable characters.
- Sonic & All-Stars Racing Transformed: A Nightopian appears driving NiGHTS shapeshifted as a vehicle and a lot of Nightopians can be seen throughout the Dream Valley circuit. Additionally, a NiGHTS sticker set, which included a Nightopian sticker, was made for the game, but it was not used in the final game.
- Sonic Lost World: Sonic has to save some Nightopians who were made prisoners in the Nightmare Zone DLC stage. They appear at the very end of the level.
- Sonic Runners: A regular Nightopian and a Nightopian wearing a Christmas outfit appeared as an unlockable buddies for a limited time. The (regular) Nightopian may destroy all iron balls, spikes and enemies on screen when the player gets damaged. The Christmas Nightopian may trigger the Yellow Drill effect at random after a X combo.
Descriptions and Profiles
English bio (NiGHTS into Dreams)
"Nightopians are carefree, happy inhabitants of Nightopia. They’re born every time balls of light (called Ideya) collide. The sole reason for their existence is to have fun. Because they are incapable of doing anything else, they have no need to work together or to cooperate towards a common goal. As a result, they have no leader, and no language. What they do have, is the ability to see the consciousness of each visitor (dreamers from our world), through Ideya. When visitors arrive, the Nightopians can see their consciousness and recreate the happy world that is hidden deep inside. They’re why Nightopians, who don’t have the capacity for intelligent thought, can sing, dance, and even go fishing."
- The Nightopians were likely designed after the Coneheads, a race of aliens that used to appear in early Japanese advertisements for the SEGA Saturn in 1994.
- The Chaos from the Sonic the Hedgehog series bear many physical similarities to the Nightopians.
- Additionally, in some Sonic games, the Chaos were voiced by Tomoko Sasaki, the same person who voiced the Nightopians in Journey of Dreams.
- In an interview, Yuji Naka revealed that what inspired him to create the Nightopians A-Life system were games like Lemmings and Populous.
- He also revealed that they considered making a separated game just for the A-Life system.
- The developers wanted to let the players be able to name each individual Nightopian in NiGHTS into Dreams. However, that would make the save data too large and only people with the backup RAM carts would be able to play the game. 
- During the month of December, the Nightopians in the Christmas NiGHTS version of Spring Valley may sing classical songs, such as Ode an die Freude by Ludwig van Beethoven and Stille Nacht by Franz Xaver Gruber, at random occasions.
- In the game Burning Rangers, there is a location named after the Nightopians called "Pian Alley", which appears in the third mission of the game.
- The Playstation 2 version of NiGHTS into Dreams was planned to have a Halloween-themed Level where the Nightopians would have their own Halloween costumes. However, the level was scrapped. The Nightopians' Halloween costumes can still be found in the game files though.
- According to the (now unavailable) NiGHTS into Dreams English website, the Nightopians are said to have no leader, which is odd, considering the King Pian exists.
- Also according to the website, the Nightopians are said to be created when two Ideyas collide. This contradicts with what is shown in the games, where they are born from eggs.
- Making all of the Nightopians reach maximum happiness in a level from NiGHTS into Dreams will make them sing Dreams Dreams in the Nightopian Collection of that specific level. 
- The Nightopians are one of the nine NiGHTS characters who have appeared in every NiGHTS game. The others are NiGHTS, Reala, Wizeman, Elliot, Claris, Mepians, the King Pian and Shleeps.
- NiGHTS: Journey of Dreams Full cast & crew
- NiGHTS into Dreams English Website (now unavailable)
- King Pian guide by Saturn Memories
- NiGHTS into Dreams Manual
- Designing the A-Life System – 1996 Developer Interview
- Christmas NiGHTS gameplay (Nightopians sing at 1:11)