Undertale is preparing to celebrate its 10th anniversary with a special live stream this month, while creator Toby Fox has also provided a new update on the ongoing development of Deltarune. In his latest newsletter, Fox confirmed that Chapter 5 of Deltarune will not be released during the first half of 2026, despite steady progress being made.
The celebratory stream is scheduled for September 20 and 21, beginning at 4 PM PT on both days. The event will feature a full playthrough of Undertale, split into two sessions due to its length. Fox remarked humorously on the challenge of filling so much time on stream, joking about whether anyone would truly enjoy watching the entire playthrough. This anniversary event follows in the footsteps of previous Deltarune streams, where earlier chapters were revisited and discussed.
Fox’s update also highlighted the status of Deltarune Chapter 5, which is currently in advanced development but still requires polishing and refinement. He explained that while the early sections are nearly finished, the final segments remain in a rough draft or prototyping stage. Around 85 percent of the chapter’s cutscenes are in draft form, though approximately 20 percent of them will need additional polish. Regular enemy designs are largely complete, with work even beginning on enemy patterns for the following chapter. Boss encounters have also been planned and partially implemented.
“Currently, we have one main deadline: I want to begin the translation by the end of 2025,” Fox wrote in the newsletter, adding that while gameplay tweaks may still be possible at that point, large-scale story revisions would no longer be feasible. He further clarified, “Factoring the localization and testing… I don’t think that the game will be released in the first half of 2026.”
Beyond the Deltarune update, Fox used the newsletter to reflect on his early creative roots, particularly his work on Homestuck, a webcomic that significantly shaped his career. He shared anecdotes about composing for its music team, building industry connections, and even voicing a character in a new Homestuck animation project alongside veteran actor Richard Horvitz.
Fans were also treated to updates on other projects, including his musical contributions to a remake of the cult RPG OFF, as well as upcoming musical albums inspired by both Undertale and Deltarune. In addition, new merchandise was teased through Fangamer, continuing the legacy of community-driven support that has accompanied Fox’s work for the past decade.
Undertale originally released in 2015 and quickly rose to acclaim for its inventive combat mechanics, branching storylines, and unique characters. Deltarune, a separate yet thematically connected project, began with free chapter releases in 2018 and 2021 before expanding into a paid release in 2025 with Chapters 3 and 4. Future chapters, including the much-anticipated Chapter 5, will continue to be added as free updates.
