Developers on Undertale Yellow , formally listed as Team Undertale Yellow , are people who helped develop the game. The team has grown to about 27 people over time, with about 10 people actively working on the game at all points. [ 1 ] [ 2 ] Each team member has contributed in areas of music, programming, narrative design, sprites, concept art or just general game concepts, with some contributing in multiple areas and many collaborating on individual sprites, music or programming.
Development of Undertale Yellow started on February 4, 2016, [ 3 ] after Master Sword finished playing Undertale in late January and had several ideas about a fangame for the Justice SOUL human. He posted on Twitter and Reddit about it, and in a few days they had the base team that went mostly unchanged during development. [ 4 ] [ 5 ] [ 6 ] At the time development started most of the team were teenagers, and Day describes that one of the hardest things during development was disagreements between team members, but by 2019 they found a rhythm of how they like to work. [ 7 ]
The team's official Twitter account was made in February 2016, the Game Jolt page in March and the Discord server in April. Early development of the game used to be over the public subreddit, [ 8 ] which was created on the day development started, but later on switched to Discord. [ 9 ]
Josiah Rodney Smith , better known as Master Sword , is the director of Undertale Yellow , as well as a composer, writer and room designer on the game. He came up with the idea for Undertale Yellow one night after he finished playing Undertale , when a bunch of ideas flooded his head. Soon after, he posted on r/gamemaker [ 5 ] and r/Undertale [ 6 ] and then founded r/UndertaleYellow which, for a time, had some development work. [ 8 ] At the time of team recruitment, Master Sword had around 15000 subscribers on his YouTube channel due to his involvement in the Game Grumps (and other YouTubers') remix scene, which helped him recruit other developers on the game easier. [ 12 ]
During development, his work was mostly on the game's writing and music. He is credited for 100 out of 135 tracks in the Undertale Yellow Soundtrack , as well as for 12 out of 17 tracks in the Demo OST . His favorite tracks to compose were relaxing songs. [ 13 ] Additionally, he created Slurpy . [ 14 ] His birthday coincides with the day that Axis Model 01 got rejected by Asgore .
Master Sword is known for his work on the Spooky Month series by Sr Pelo as a composer, as well as his Game Grumps remixes, which he posts on his YouTube channel. He also plays in a band called Chasing Da Vinci with his siblings.
His username, MasterSwordRemix , is a reference to the Master Sword from Zelda. He makes a cameo in Undertale Yellow as Rodney , who is named after his middle name. His mascot, reminiscent of Rodney (due to being based on Master Sword's previous avatar, a purple Triforce ), was designed by Figburn. Master Sword only feeds him Ritz Crackers and small rocks. [ 15 ]
He is not British. [ 16 ]
Julian , better known as Figburn , is a spriter, composer and room designer on Undertale Yellow . He found the development team through one of Master Sword's tweets, later posting concepts on the subreddit and emailing them to Master Sword before finally getting invited to the development server. [ 8 ]
In Undertale Yellow he has worked on designing enemies, NPCs and shopkeepers, such as Ed , Guardener and Sousborg . [ 18 ] [ 19 ] [ 20 ] His earliest design for the game was Crispy Scroll , way back in Undertale Yellow 's demo. His overworld contributions also include work on the outside of the Estate [ 21 ] [ 22 ] and cleanup work on the New Home buildings. [ 23 ] He made Chujin 's face sprites in his video tapes, [ 24 ] did cleanup work on Ceroba's battle , [ 25 ] helped revamp the introduction screen, [ 26 ] and sprited the two pictures from Undertale Yellow to match Temmie Chang 's art style. [ 27 ] [ 28 ]
He has directed most teasers and trailers of Undertale Yellow , as well as contributed artwork for the game's Game Jolt devlogs. He has also contributed concept art, [ 29 ] [ 30 ] and pitched the Chair Man fun value. [ 31 ]
As a musician, he has composed or helped compose 20 tracks in the OST, including TENTH LEVEL LOCKDOWN , A Mother's Love , END OF THE LINE_ and Retribution .
Through his work on Undertale Yellow he was able to gather enough Twitter followers to work freelance for a while. [ 32 ] He has also worked on several other games, including:
While he has no clear cameos in Undertale Yellow , there is an NPC named Flame Guy , whose alternate internal name is "Fireburn," likely as a reference to Figburn's old username. Additionally, Know Cone 's Fig attack might be referencing Figburn. His birthday coincides with the day Chujin pitched the blueprints for Axis to Asgore .
He calls his avatar "the idea," likely as a reference to the Mario, the Idea vs. Mario, the Man meme. [ 36 ] Among the development team, he is Slurpy 's biggest defender. [ 37 ]
Collin , better known as AeroArtwork , is a spriter and concept artist on Undertale Yellow . He won the enemy contest in 2017 with his design of the Flower Girls , [ 39 ] and later joined the development team in January 2022. [ 40 ] At the time he joined the team, development was at the Steamworks Factory. [ 41 ]
In Undertale Yellow he is mostly responsible for the Pacifist Route final battle against Ceroba and events surrounding it. He designed Ceroba's final form, [ 42 ] most of her attacks, [ 43 ] sequence of events throughout the battle [ 44 ] as well as storyboarded and animated the credits sequence. [ 45 ] He describes this as one of the most important things he ever had to work on. [ 25 ] In August 2022, Master Sword said that only the final battle and the credits are left to be done for the Pacifist Route, that AeroArtwork has been spearheading their development, and that he would not have added so much animation (but that he thinks it's looking great). [ 44 ]
Considering he joined late into the development, his contributions mostly consisted of endgame content, such as Zenith Martlet design, [ 46 ] some content for the Meta Flowey fight [ 47 ] [ 48 ] New Home , [ 49 ] Steamworks, [ 50 ] [ 51 ] [ 52 ] and the Estate . [ 53 ] His other character work includes face sprites for Ceroba, [ 54 ] [ 55 ] Chujin [ 56 ] and Kanako , [ 57 ] [ 58 ] as well as concept art for the two pictures that Figburn later sprited. [ 27 ] [ 28 ]
Aside from endgame content, he contributed secrets to the game, most likely during the development's polish phase. This consists of the Macro Froggit battle, [ 59 ] several fun value events, [ 60 ] [ 61 ] as well as hiding a lot of dog faces around the game. [ 62 ]
He organized a few Undertale Yellow -related streams together with other developers, such as the Undertale Yellow charity stream on Prismathon and the chat request art stream in April 2024, and he sometimes streams Undertale Yellow content on his Twitch channel. His girlfriend Malloree ( @tea_bubbled ) has playtested Undertale Yellow and inspired some of the development decisions, such as the stars in Starlo 's room. [ 28 ]
His birthday coincides with the day that Axis Model 08 malfunctioned and Chujin got fired from his job. He has also contributed to this wiki two weeks prior to Undertale Yellow 's release to correct Frostermit 's name in the final game.
Day , known by her username of AWildDaydreamer , is a writer and room designer on Undertale Yellow . She is Undertale Yellow 's lorekeeper—a person who ensured that Undertale Yellow 's lore aligns with Undertale 's. Master Sword pointed out that this is a very important role because he did not fully grasp Undertale 's lore at all times, whereas Day was at one point able to recite it by heart. [ 64 ] She is a friend with Pippy, who found out about the game through Master Sword's Reddit post, and then kept asking Day about Undertale lore which eventually led to Day joining the development team. [ 65 ]
Aside from writing, she worked on the Clover sprite redesign [ 66 ] and the Clover mod for Rivals of Aether . [ 35 ]
Deadkat is a spriter and programmer on Undertale Yellow . He joined the development team around July 2019 as a spriter, [ 67 ] and later got to work on programming as well.
As a programmer, he worked on the El Bailador battle, where he refactored the code to more easily rechart the fight based on audio-only cues and made it slightly easier. [ 68 ] He created the palette swap shader , which allowed reusing characters' sprites in Snowdin , Steamworks and Dunes caves without having to create new sprites with different palettes to suit those areas. [ 69 ] He programmed several battle backgrounds, such as those for Zenith Martlet , [ 70 ] Ceroba , [ 71 ] and Flowey . [ 72 ] He also worked on Patchworked and Clay phases of the Meta Flowey battle. [ 73 ] [ 74 ]
As a spriter, he created several Dunes NPCs , [ 75 ] as well as the big unused train sprite in the Wild East . [ 76 ] He also got to design plant sprites in the Estate [ 53 ] as well as Dalv 's winter uniform. [ 77 ]
His birthday coincides with the day that Axis Model 04 shot of one its gloves at Asgore . Soon after joining the team he got to point out the game was breaching the Geneva Convention for using a sprite with a red cross. [ 78 ]
GlitchedPie is a spriter, composer and room designer on Undertale Yellow . He joined the team around June 2017, as a result of a spriter search. [ 80 ]
As a spriter, he did background art for the Estate exterior, Chujin 's grave, all shops in the game, as well as the New Home balcony. [ 81 ] Together with AeroArtwork, he worked on the Macro Froggit battle, [ 59 ] as well as hiding dog faces within the game. [ 62 ] He suggested the Flawed Pacifist Ending [ 82 ] and worked on corrupted versions of bosses in the Flowey boss fight. [ 83 ] He also revamped the introduction screen along with Figburn. [ 26 ]
As a composer, he worked on four tracks in the OST: Going Up , Golden Opportunity , specimen: clay and Flock Together . He also came up with lyrics to specimen: clay . [ 84 ]
His birthday coincides with the day Axis Model 07 refused to enter the Throne Room.
Spasco , previously known as SpartanScooter , is the lead programmer on Undertale Yellow and a sound designer. He joined the team in its early days, [ 5 ] after Master Sword commented on his Annoying Dog fight fangame. He programmed most of the Undertale Yellow demo, with MysteryRacer's help after they brought him to the team. [ 87 ]
He decided to step down to secondary programming after the demo and let MysteryRacer rebuild the overworld and battle engine, as the demo's code was not built for the long term. [ 88 ] However, in September 2018 the team announced that the overworld (but not battle) engine by MysteryRacer was being reverted to the demo engine, because Spasco was mostly working on the overworld parts of the game and had a harder time adapting to MysteryRacer's engine. [ 89 ] In the final game, he's credited as the lead programmer, and helped release the v1.1 patch.
Aside from Undertale Yellow , he programmed the Clover mod for Rivals of Aether , [ 35 ] and worked on Neon: Energized and Neon Rhythm with Figburn. He is also known for his work on other Undertale fangames, such as Bad Monday Simulator .
After the release of Undertale Yellow , Spasco also worked on the official Undertale 10th anniversary stream . [ 90 ]
Nero , known by her username of NeroSensei , is a concept artist on Undertale Yellow . She has worked on designing or illustrating multiple characters, such as Starlo , [ 91 ] Donald Glover , [ 92 ] Mail Whale , [ 93 ] and Slurpy . [ 14 ] Most of her contributions are in the form of sketches. [ 94 ] It also appears that she helped in the design of Martlet . [ 95 ] [ 96 ]
Cleo , better known as TeleviQ , is a spriter and concept artist on Undertale Yellow . He joined the team in February 2017. [ 97 ]
He designed or helped design Ceroba , Chujin , Kanako , Axis , Moray , [ 98 ] Sir Slither , Bowll , Jane Doe , Rodney's Band , Orion , [ 99 ] Vendy , [ 100 ] Boba Drinker , Kanako's Friend (whom he calls Sadie), [ 101 ] [ 102 ] and Fortune Teller . [ 103 ]
Evan G , better known as NoteBlock , is a composer and concept artist on Undertale Yellow . Similarly to Master Sword, he mostly posts remixes on his YouTube channel.
He composed or helped compose 25 tracks in the Undertale Yellow Soundtrack , such as BEST FRIENDS FOREVER , AFTERLIFE , A Mother's Love and Undertale Yellow . He also made FINAL STAND , a previous version of Retribution , which was left unused for being too cheerful. [ 105 ]
He also did concept art for several characters in the game, mostly in Snowdin , including Penilla , Frostermit , Slurpy , Insomnitot , Mo , [ 106 ] Mail Whale , Blankie , Lounger and El Bailador . [ 107 ]
He makes a cameo in the game as himself from Rodney's Band .
Luis Sies , better known as MyNewSoundtrack , is a composer on Undertale Yellow . At some point during development, he had to step down due to life issues. [ 109 ] Similarly to Master Sword and NoteBlock, he mostly posts remixes on his YouTube channel.
He composed or helped composed 20 tracks on the Undertale Yellow Soundtrack , such as Meltdown , TENTH LEVEL LOCKDOWN , Guns Blazing and Remedy . He has helped Master Sword arrange many boss battle themes that he couldn't pull off. [ 110 ] He also helped create trailer music for the Clover mod in Rivals of Aether . [ 35 ]
He makes a cameo in the game as Soundtrack from Rodney's Band .
Pippy V. , also known as PippyInATopHat , is a writer on Undertale Yellow . She joined the development team after seeing Master Sword's Reddit post, and later on brought Day onto the team as a lore consultant. [ 65 ]
She has a Twitch channel on which she mostly streams speedruns.
Vegard Jensen is a spriter on Undertale Yellow . He joined the team around June 2017, as a result of a spriter search, along with GlitchedPie. [ 80 ] He designed or sprited Dalv , Martlet , Starlo , Axis , Frostermit , Insomnitot , Mo , The Shufflers , Flame Guy , Donald Glover , Dunes Rabbit , Maury , Lounger , Sandstorm Stander , Fan Fan , Snake Miner , Drinki , Aunt Glover , Fortune Teller , Red , Gamer , Crestina , Hermit and the Dunes tileset. [ 113 ] It appears that his contributions spanned from 2017 to 2019. [ 114 ]
MysteryRacer is a programmer on Undertale Yellow . He joined the team in September 2016 to help finish the Undertale Yellow demo, [ 87 ] and then took on the role of the game's primary programmer after Spasco stepped down. [ 88 ] However, in September 2018 the team announced that the overworld (but not battle) engine by MysteryRacer was being reverted to the demo engine, because Spasco was mostly working on the overworld parts of the game and had a harder time adapting to MysteryRacer's engine. [ 89 ]
The battle engine he introduced into the game is based on his Undertale Customs fangame. While implementing it, he added many features to the demo battle engine, such as damaged enemy states and health bar statuses when attacking. [ 116 ] The switch to Undertale Customs engine also introduced two unused enemies into the game, Craniex and Ms. Mettaton . For Master Sword's 17th birthday, he also implemented an unused MasterSwordRemix enemy into the game, whose sprites were removed. [ 117 ]
Gaziter is a spriter and concept artist on Undertale Yellow . Their contributions include Honeydew Shopkeeper , [ 19 ] Clover 's sprite redesign, [ 66 ] concept art for Maury [ 119 ] and the Estate . [ 21 ]
They work as a character designer and artist on a tactical roguelike deckbuilder game Wildfrost , as well their personal project Sparknight .