Undertale Adventures X Beginner's Guide: First Session to First Reroll

Undertale Adventures X is a Roblox tower defense built on a premise Undertale players already understand: the game's characters are your towers, and everything that tries to cross the map is your problem. You summon units, place them along the path, and survive waves — and the difference between a struggling account and a compounding one is not reflexes, because there are none to speak of. It is decisions: what you summon, where you place it, and when you start rerolling the stats that decide how far a unit carries you. This guide is the first-session path through all of it, in the order a new player actually needs it.

Step One: Land in the Lobby and Take the Free Money

The first minute of Undertale Adventures X should be spent not playing. Launch the game, load into the lobby, and look to the right side of the screen for the Codes button — the game ships with six working codes as of October 20, 2026, and the two milestone codes alone put 100 Trait Rerolls and 11,110 Souls on a fresh account before you have won a single wave. That is the single largest free resource injection in the game, and skipping it means grinding for hours to earn what a two-minute redemption pass delivers instantly. The full list, with every reward itemized, is on the verified codes table, and the redemption steps take under a minute per code.

Why this is step one and not a side note: Souls and Trait Rerolls are not consolation prizes — they are the inputs to the reroll systems that this entire game's progression hangs on. Starting the game with a full tank of both means your first meaningful unit can be improved immediately, instead of in a week.

Step Two: Summon Your First Units

With the codes banked, head to the summoning system and spend into your first roster. Units in Undertale Adventures X are Undertale characters pulled through the game's summon mechanic, and every one of them fills a role on the battlefield — the units codex breaks the roster into the three profiles that matter: main damage dealers, area-clearing units, and support. Do not overthink the first pull session. The early game does not demand an optimized roster; it demands a roster, plural, because a tower defense with one tower is a loading screen with extra steps.

The beginner mistake to avoid is hoarding. Summoning currency sitting unspent is wave pressure you failed to answer, and early waves are tuned to be clearable with whatever the first few pulls deliver. Pull, place, and learn what each unit actually does when a wave reaches it — that observation is worth more at this stage than any tier ranking, and it is the foundation the best units guide builds on later.

Step Three: Survive the First Waves

Placement is where tower defense stops being a menu and starts being a game. Three habits carry a new player through the early waves. Place damage where the path gives you the most exposure time — a bend or a long straight that units cross slowly multiplies every point of damage you own, while a spot enemies sprint past wastes it. Spread roles instead of stacking them — one solid main damage dealer backed by an area-clearing unit answers a mixed wave better than three copies of the same profile, because the wave that slips past raw single-target damage is the one that ends the run. Watch where your defense actually breaks — an early loss tells you exactly which role your roster is thin in, and that is where the next summon should go.

Losing early waves is information, not failure. The game is designed for repetition: each run teaches the wave patterns, feeds resources back into the account, and makes the next attempt stronger.

Step Four: Know When to Start Rerolling

The reroll systems are the game's long game, and the timing question is the one beginners get wrong in both directions. Rerolling too early — before you have units worth improving — burns Souls on stats that will be replaced the moment you summon something better. Rerolling never at all leaves you clearing waves with units carrying traits you would have rerolled away for free. The practical trigger: start rerolling when you have a unit you are still using several sessions later. A main damage dealer that has survived three or four runs in your lineup has earned the investment; reroll its Soul and Trait values through the systems detailed in the Soul and Trait reroll guide, and let the throwaway units wait.

The economy behind that decision is on your side if you redeemed step one. Souls farm at a steady rate once you know the route — the farming guide covers the lobby-based route the community uses — and the milestone codes keep topping the tank up. Rerolling is a game of volume: the players with the strongest units are not the luckiest, they are the ones who rerolled the most times with the resources to keep going.

FAQ

What should I do first in Undertale Adventures X?

Redeem all six working codes from the Codes button on the right side of the lobby, then summon. The codes deliver 100 Trait Rerolls and 11,110 Souls from the milestone line alone, which funds your entire early progression.

Do I need Robux to progress?

The verified progression routes in this guide are free: codes, summoning through play, wave runs and rerolling cover the loop. Treat any claim that progression requires Robux as marketing, and treat any "free Robux" code offer as a scam — codes here deliver Souls, items and rerolls, never Robux.

How do I know if a unit is worth rerolling?

Longevity is the test. A unit that stays in your lineup across multiple sessions has proven itself; reroll that one. Units you swap out within a session or two are not worth the Souls yet.

What if I lose my first waves?

Normal and useful. Early losses identify which role your roster lacks — single-target damage, area clear or support — and point the next summon at the gap. The loop only compounds if you keep playing it.