Undertale Adventures X Is Live: Codes & Release Guide

Quick answer: Undertale Adventures X is now live on Roblox under Side Productions, and it has become one of the platform’s fastest-rising experiences today. The current Roblox page labels the game [RELEASE] Undertale Adventures X and describes it as an Undertale-inspired tower defense game where you defend a base with Undertale units, level them and improve them with traits.

The sudden search spike is unusual: Rival Ducks’ Roblox radar identifies Undertale Adventures X as today’s breakout experience, with a relative activity increase above 44,000% in its latest snapshot. Rotrends also places it at the top of its October 7 daily trending list. That surge creates a freshness gap because many search results still use the older Undertale Adventures TD name or show maintenance/Christmas-era information rather than the current X release state.

Undertale Adventures X at a glance

The safest starting point is the official Undertale Adventures X Roblox page. That page now says the game is live and identifies Side Productions as the creator.

Is Undertale Adventures X a new game?

The current X release is new as a live release state, but the underlying Roblox experience is not newly created. Roblox tracking pages show the experience ID dates back to July 2024 and previously appeared as Undertale Adventures / Undertale Adventures TD.

That history explains why search results are confusing. You may see:

• old pages calling it Undertale Adventures TD;
• older Roblox snapshots showing a Christmas update;
• maintenance-state pages from the days before the current release;
• new pages and Roblox itself using Undertale Adventures X.

Players looking for current information should prioritize sources updated after the X release went live rather than assuming a 2025 guide reflects the present build.

Why is Undertale Adventures X trending today?

The strongest signal is not a vague social-media mention; it is the movement in Roblox discovery data. Rival Ducks Radar identifies Undertale Adventures X as today’s breakout experience with a reported +44,905% relative increase. Rotrends’ October 7 trending page also places it at the top of its daily rising list.

That kind of acceleration usually happens when a previously quiet or unavailable experience returns, relaunches, receives a major update, or starts receiving strong discovery distribution. In this case, the official Roblox title itself now says RELEASE, supporting the relaunch interpretation.

Because Roblox discovery can change hour by hour, the exact player count is less useful than the direction of movement. Some trackers update different parts of their databases on different schedules, so one page may still display a stale pre-release CCU while its trending index already detects the new surge.

How Undertale Adventures X plays

The official description gives four core ideas:

1. It is a tower defense game based on Undertale.
2. You defend your base from monsters.
3. You use Undertale-themed units as your defensive roster.
4. You level those units and strengthen them through traits.

That means new players should think less like an action RPG and more like a traditional Roblox tower defense game: unit selection, placement, upgrades and trait quality matter more than direct character movement during the wave.

What should new players focus on first?

1. Learn the placement lanes before chasing rare units

A high-rarity unit does not automatically fix poor placement. On your first runs, watch where enemies enter, how quickly they move, where paths overlap and where your units can cover the greatest number of tiles or seconds of travel.

2. Upgrade a small core roster

Spreading early resources across every unit can slow progression. Build a small dependable group that can clear the content you currently farm, then expand once your income becomes more reliable.

3. Treat traits as long-term optimization

The official description specifically highlights traits, so rerolls are part of the progression loop. Do not burn every reroll immediately on weak temporary units if you know you will replace them soon.

4. Recheck the live update state

The game has just moved from maintenance/older naming into the X release state. Menus, rewards and balance can change quickly during a relaunch window. If an older guide conflicts with the live client, the current game should win.

Undertale Adventures X codes: what works right now?

This is the area where the old and new naming causes the most confusion. Several code databases still list Undertale Adventures TD codes from the pre-X version, including:

• UPDSEP25!
• XMASUPDATE2025
• SORRYAFTERTALEDELAY
• THANKYOU10kMEMBERS
• THANKYOU12MILLIONVISITS
• JUNE10UPDATE

Game.Guide was still tracking those six strings on October 1, 2026. However, not every code tracker agrees that all six are currently active, and the X release may have changed code validity or redemption behavior.

For that reason, AVARIXO is separating historically reported codes from verified X-release codes. At the time of this check, the official X Roblox description does not publish a new October 7 code list.

How to redeem Undertale Adventures codes

Older versions of the experience used a dedicated Codes button, often shown with a bird icon. The historical redemption flow was:

1. Launch Undertale Adventures.
2. Open the Codes button.
3. Enter the string exactly, including capitalization and punctuation.
4. Submit the code and check whether the reward appears.

If the X release moves or replaces that menu, follow the current in-game interface. A failed old code does not necessarily mean you typed it incorrectly; it may have expired or been disabled during the relaunch.

Which old code should you test first?

UPDSEP25! is the newest code in the current third-party histories reviewed for this guide, added in August 2026. That makes it a more sensible first test than 2025 Christmas codes. Still, it should not be described as guaranteed until it is confirmed in the live X build.

The older THANKYOU12MILLIONVISITS code was previously associated with a Justice Vial, Magu Fruit and Empty Gun. Those rewards belong to the earlier Undertale Adventures TD era, so their current usefulness or compatibility may differ after the X release.

Why old Undertale Adventures guides can be misleading now

The first-page search results contain a mix of timestamps and game states:

• Pocket Tactics’ main codes article was last substantially refreshed in 2025.
• Pro Game Guides’ detailed code page dates to June 2025.
• some game trackers captured a maintenance state shortly before release;
• the official Roblox page now uses the Undertale Adventures X release title.

That is a classic freshness gap. An old guide may still be useful for basic mechanics, but it should not be treated as the final word on current codes, player counts, menus or balance.

Is Undertale Adventures X the same as Undertale Adventures TD?

It uses the same Roblox experience lineage and developer, but the current branding is Undertale Adventures X. Think of X as the current release state of the established Undertale Adventures experience rather than an entirely unrelated Roblox game.

This matters when searching. A page about “Undertale Adventures TD” may contain historical information that still applies, but check its update date before relying on it for current codes or meta advice.

What is confirmed and what is still changing?

Frequently asked questions

Is Undertale Adventures X free?

The Roblox experience is accessible through Roblox. Optional gamepasses or in-game purchases may exist, but the base experience is launched from the standard Roblox page.

Who made Undertale Adventures X?

Side Productions.

Is it a tower defense game?

Yes. The official description explicitly calls it a tower defense game based on Undertale.

Are there working Undertale Adventures X codes?

Older Undertale Adventures TD code lists still exist, but the official X release description does not currently publish a new verified October 7 list. Treat old codes as candidates to test rather than guaranteed X-release rewards.

Why do some websites call it Undertale Adventures TD?

That is the older branding used by the same Roblox experience before the current Undertale Adventures X release state.

Why are player-count sites showing different numbers?

The relaunch is moving quickly and trackers poll Roblox at different times. A trend page can detect a sudden spike before a separate cached game-detail page refreshes.

For more rapidly changing Roblox coverage, visit AVARIXO’s Gaming section and our latest Anime Dice Update 7 guide.