Undertale Adventures X Tier List

Undertale Adventures X has no official tier list, no published stat blocks and no DPS table, so any ranking is a judgment call. This one is built from three things that are actually checkable: the game's six rarity bands, the role each Unit fills, and the community consensus that shows up consistently across guides and videos in October 2026.

• S tier — the Units community guides name as endgame anchors
• A tier — the Legendary Rare band that carries mid-game teams
• B tier — Ultra Rare specialists worth keeping
• C tier — Commons and Rares that are stepping stones
• The real ranking factor — trait quality, not the Unit's band

How This List Was Built

Three inputs, in order of reliability:

1. Rarity bands from the community wiki. Common, Rare, Ultra Rare, Legendary Rare, Mythical, Secret. This is objective: the game assigns the band.
2. Role fit. A Unit that does a job no other Unit on your team does is worth more than a Unit that duplicates one you already have.
3. Community consensus. Guides and videos covering the game in October 2026 consistently name the same handful of Units as the top of the meta. That consensus is evidence of what works in practice, even without numbers.

What is deliberately not used: invented DPS figures, invented percentages, and "tier lists" copied from other Undertale tower defense games.

S Tier: The Endgame Anchors

Community guides covering the October 2026 build consistently name five Units at the top: Sans, Asriel, Mettaton NEO, Undyne and Papyrus.

Four of those — Sans, Mettaton NEO and Undyne — are confirmed by the community wiki's rarity list, sitting in the Mythical, Secret and Legendary Rare bands respectively. Papyrus sits in Legendary Rare. Asriel does not appear on the wiki's July 2026 roster at all, which is the clearest signal that the roster has grown since that page was last edited.

Why these five:

• Sans variants occupy the entire Mythical band, and Mythical is the highest summonable band. Any account that pulls one has an anchor.
• Mettaton NEO is a Secret-band Unit, which puts it among the rarest things in the game.
• Undyne and Papyrus are Legendary Rare, which is the band a free-to-play account can realistically reach.
• Asriel is named by community guides as a top tower, and its absence from the wiki list is a gap in the wiki rather than evidence against it.

A Tier: Legendary Rare

The Legendary Rare band is the backbone of most accounts, because it is high enough to matter and low enough to actually pull.

KnightKnight deserves a note: a community guide for the Neutral Corridor fight names Knight Knight as a DPS component of a working composition, which is the kind of concrete evidence that rarity alone cannot give you. When a Unit shows up in a specific clear, that is stronger evidence than its band.

B Tier: Ultra Rare Specialists

Ultra Rare is where the specialists live. These Units rarely anchor a team, but several of them do a job that nothing higher can replace.

The two Royal Guards are worth keeping even at B tier because "durable frontline" is a role that does not get better with rarity; it gets better with placement.

C Tier: Commons and Rares

The Common and Rare bands are stepping stones. That is not an insult — the game is designed so that your first team is made of them, and several have specific uses.

• Vulkin, Tsunderplane, Heats Flamesman are late-area Commons, which means they were added to a Hotlands banner and often carry fire-typed damage that the Ruins Commons do not.
• Onion San and Scared Donut Guy are Rare-band Units that show up in community memes more than in meta teams.
• Froggit, Whimsun, Loox, Moldsmal are the literal first wave of the game. Use them, do not invest in them.

The C-tier rule: upgrade a Common only if it is your economy Unit and only as far as it takes to clear Ruins Act 4.

The Trait Multiplier

Here is what actually moves a Unit between tiers: traits.

Traits are rolled in the lobby's Upgrades facility. The game's own description names traits as one of the two progression axes, and codes hand out Trait Rerolls in bulk (25 at a time in the current code payout). A well-traited A-tier Unit will out-perform a badly-traited S-tier Unit in the same role.

That means the tier list is really a list of build targets, not a list of wins. The traits guide explains which roles want which kinds of buffs.

What the Tier List Cannot Tell You

Three gaps are worth naming, because other tier lists paper over them:

No stats. The game publishes no damage, range or attack speed numbers. Any list with "+12,400 DPS" is fabricated.

No rates. Summon rates per rarity band are not published, so "easy to get" is a relative statement, not a probability.

No matchup data. Whether an S-tier Unit beats a specific boss depends on the boss's gimmick. The Corridor fight, for example, has a dodge mechanic that ignores damage over time entirely — which makes any DoT-based Unit worse there regardless of tier.

How to Use This List

Do not chase S tier. Do this instead:

1. Pick the highest-band Unit you own that fills a role you are missing.
2. Roll one trait on it.
3. Field it in the Act you are stuck on.
4. If it does not help, the problem is the role you are missing, not the Unit's band.

The Units list has every confirmed name by band, and the beginner guide covers the four-role team structure this list assumes.

Sources and Further Reading

• The rarity bands used to build this ranking: the community wiki's unit roster
• The current code payout: GamesRadar's Undertale Adventures X code page

Official source: Undertale Adventures X on Roblox — the official description confirms that players defend a base with Undertale units and strengthen them with traits.

Frequently Asked Questions

What is the best Unit in Undertale Adventures X? Community guides consistently name Sans, Asriel, Mettaton NEO, Undyne and Papyrus. The game publishes no official ranking.

Is Mythical better than Secret? Both are top bands. Which is better depends on the Unit's role and its traits, not on the band name alone.

Should I reroll traits on a low-band Unit? No. Rerolls are scarce unless you are redeeming codes. Spend them on a Unit you plan to keep.

Why is Asriel not on the Units list? The community wiki's roster was last edited in July 2026. Asriel is named by community guides, so the wiki is behind the game.

Can a Common Unit be useful? Yes, as an economy Unit early. Do not upgrade one past the point where you can clear Ruins Act 4.