1991–2009: Early life and work Robert F. Fox was born on October 11, 1991, in
Manchester, New Hampshire. One of his early projects was the
EarthBound Halloween Hack, a Halloween-themed ROM hack of
EarthBound, which released in 2008. He then moved on to compose music for Andrew Hussie's 2009 webcomic
Homestuck during his senior year of
high school. While he did not initially respond when Hussie started a
Music Contribution Team in April 2009, Hussie took note of his work when Fox started uploading piano covers of the webcomic's music on the
MS Paint Adventures forums. becoming a "breakout hit" and "pop-culture phenomenon".
Undertale has received nominations for a
British Academy Game Award, three
Game Awards and
D.I.C.E. Awards. Fox worked on the entire game independently, besides the art assets to avoid relying on others. Fox recruited
Temmie Chang to work on art for
Undertale. Fox conceptualised the character designs for Undertale during college, drawing them in his notebook. Following its release,
Undertale garnered an
extensive fanbase. Fox commented that he did not mind if people stated that they did not like
Undertale, saying that it was "not for everyone". Also in 2016, Fox wrote that his personal opinion was that
Undertale was still "niche" and deserved an "8/10" review score. He also became a contributor to the
A Profound Waste of Time magazine. Fox was then chosen to be part of the 2018 Games
Forbes 30 Under 30 list for his role in creating
Undertale; by which point had sold over 2 million copies. The success of
Undertale, especially in Japan, afforded Fox the opportunity to meet
Super Smash Bros. creator
Masahiro Sakurai.
Sans, a character from
Undertale, was later included in
Super Smash Bros. Ultimate as a Mii costume available through
downloadable content, along with an instrumental composition "
Megalovania", for which Fox provided a new arrangement.
2018–present: Deltarune '' Fox initially conceived of the idea for his game
Deltarune in 2011, with an initial version being created in 2012 before being abandoned. On October 30, 2018, Fox posted a request for fans of
Undertale to check its official
Twitter account in 24 hours. The following day, Fox released the first chapter of
Deltarune for free under the guise of a "survey".
Deltarune takes place in a
parallel universe to the setting of
Undertale, with Fox describing it as being "more enjoyable" to those that had completed it. At the time, Fox stated that he did not wish to spend longer than seven years on the project; he expressed interest in assembling a team to aid development, stating that without one he had "absolutely no estimation of its completion". After
Deltarune had been playable for several months, Fox stated he had hope he would complete its remainder, saying: "Slowly I'm writing and drawing it all out." He stated that he had already written about 50 songs past Chapter 1. On September 17, 2021, Fox released the second chapter of
Deltarune for free since "the world has been really tough for everybody recently", referring to the struggles of the
COVID-19 pandemic. He released the next two chapters, 3 and 4, bundled in with the first two as a paid game on June 4, 2025; future chapters will be added to it as free updates for owners of the paid version. He is currently working on Chapter 5, which is set to release in 2026.
Deltarune is set to have a total of seven chapters. and
Game Freak's 2019 RPG
Little Town Hero, the last of which was arranged by
Pokémon composer Hitomi Sato. He also composed a track for
Pokémon Sword and Shield, and multiple tracks for
Pokémon Scarlet and Violet. He also remixed
Ed Sheeran's "
Celestial" for
Scarlet and
Violets expansion
The Indigo Disk. In 2024, he partnered with Japanese game developer
ZUN for the
Touhou Danmaku Kagura Phantasia Lost downloadable content, which included a track that combined the Touhou song "
U.N - Owen Was Her?" with
Undyne's boss battle theme "Battle Against a True Hero" from
Undertale. Fox has done voice acting work for multiple television and web series. In 2023, Fox had his voice acting debut in the animated television series
We Baby Bears. He plays a skeleton named Jared in the episode "Polly's New Crew". Fox stated that it had "been a dream of [his] to be a voice actor in cartoons". In 2025, Fox voiced
John Egbert in the
Homestuck animated pilot. == Philanthropy ==