The Backrooms update reshaped how players build their squads in Slop Tower Defense, layering secret floors and event-gated heroes on top of the standard summon pool. If you have been wondering which Slop Tower Defense Backrooms units are worth chasing and which ones you can unlock without spending a single gem, this breakdown walks through every roster slot tied to the event, including the free starting line-up, the limited banner heroes, and the rare drops most players overlook. The Backrooms also introduced alternate evolution paths for older units, so even veterans who completed the original roster have new reasons to revisit the summoning screen.
Because the event layers so many systems — banner rotations, secret floor codes, and shiny variants — players who jump in blindly tend to burn tickets on the wrong banner. Below, we map out the full Backrooms unit catalog, the requirements for each unlock, and the priority order that experienced summoners use to stretch a tight resource budget.
The Parallel Backrooms Banner Roster
The Backrooms event adds a parallel unit track alongside the main Slop Tower Defense summoning pool. Rather than replacing existing units, the new roster slots into separate banner rotations that drop during limited windows, with each rarity tier carrying its own pity system and shard requirements for evolution.
| Rarity Tier | Drop Rate (est.) | Pity Threshold | Evolution Cost | Availability |
|---|---|---|---|---|
| Common | ~55% | N/A | 20 shards | Banner pool, always |
| Rare | ~30% | 50 pulls | 40 shards | Banner pool, always |
| Epic | ~10% | 80 pulls | 80 shards | Rotating event banners |
| Mythic | ~4% | 120 pulls | 120 shards | Limited event banners |
| Hero | ~1% | 200 pulls | 200 shards | Seasonal / Backrooms exclusive |
Hero-rarity units are the headline reward of the Backrooms, because they cannot be obtained from the standard summon pool outside the event window. They follow a separate pity counter that does not share progress with the main banner, so a player who has hit 199 pulls on a Mythic banner still needs to start fresh when a Backrooms Hero banner drops.
Free Units and Starting Backrooms Roster
New players who clear the first three secret floors automatically unlock three Backrooms units without spending any tickets. According to community testing reported by the Vaulted Values X showcase on YouTube, the free starting trio covers a useful spread of roles: a single-target damage dealer, a splash-DPS option, and one support unit that buffs adjacent allies.
| Free Unit | Role | Range | Special | How to Unlock |
|---|---|---|---|---|
| Maze Striker | Single-target DPS | Medium | Bonus damage on back-row enemies | Clear Backrooms Floor 1 |
| Lamp Lighter | Splash DPS | Short | Burns enemies, deals DoT | Clear Backrooms Floor 2 |
| Hall Monitor | Support | Long | Buffs adjacent units' attack speed | Clear Backrooms Floor 3 |
These three units form a viable early-game squad on their own, and each one can be evolved once you start collecting shards. Because the unlock path is gated by secret-floor progression rather than by gacha pulls, every player — including those who never spend — eventually has access to at least one Backrooms unit per role category. A useful primer on how the standard summon pool compares to the Backrooms roster sits in the complete Slop Tower Defense unit index, which catalogs the non-event heroes as well.
Event Units and Banner Rotations
The Backrooms event runs on a rotating banner schedule, with each banner lasting roughly 72 hours in-game before swapping to a new featured unit. Community data shared across showcase videos suggests a banner cycle of two Mythic units, one Hero unit, and one re-run slot, with the re-run slot usually reserved for units that have not been available in over a month.
Current and Upcoming Backrooms Banner Units
| Unit Name | Rarity | Banner Type | Window | Strongest Synergy |
|---|---|---|---|---|
| Flickering Wraith | Mythic | Featured | First 72h of rotation | Pairs with Hall Monitor for attack-speed chain |
| Ceiling Crawler | Mythic | Featured | Middle 72h | Splash DPS, pairs with Lamp Lighter |
| No-Clip Sentinel | Hero | Featured | Final 72h | Universal placement, no range limit |
| The Lost Clerk | Hero | Re-run | Every 4th rotation | Highest base HP, frontline anchor |
Each banner features a "rate-up" period where the featured unit's drop chance roughly doubles, so pulling during the first 24 hours of a banner is mathematically the most efficient way to land a specific unit. After the rate-up window closes, the unit remains in the pool at standard odds but no longer has a boosted rate. The pity counter is shared across the entire event pool, meaning pulls on a Mythic banner still progress toward the Hero pity at 200 pulls.
Limited Units and Time-Locked Drops
A small subset of Backrooms units are flagged as "limited" — they only drop during a single banner rotation and then leave the standard pool entirely. According to data summarized in the DinozaurPlays unit showcase, limited units do not return in re-run slots and cannot be crafted from shards after their banner closes, making them the most time-sensitive pulls in the event.
| Limited Unit | Banner Window | Reason for Limitation | Workaround |
|---|---|---|---|
| Stairwell Phantom | One rotation only | Story-gated to Act 3 | None — must pull during the window |
| Hollow Howl | One rotation only | Developer-collab event | None after banner ends |
| Yellow Flash | Two rotations | Used for next Mythic evo | Trade-in shard after banner ends |
Limited units are not strictly stronger than permanent Backrooms units, but they tend to be the only option for certain niche roles, such as the Stairwell Phantom's ability to slow bosses by 30% for 8 seconds. Players who miss the banner window either have to wait for an unlikely re-run or accept that the slot stays empty.
How to Unlock Every Backrooms Unit
Free units lean on a daily login streak plus the level-up milestone rewards that hand out a Backrooms Crate every ten levels, while event exclusives rotate through the Backrooms Event Shop on a roughly 6-week cadence — meaning the F2P track runs longest, the event track rewards checking the shop tab on reset day, and the limited gacha path is the only one where a specific Backrooms unit like the Level Editor or The Partygoer can actually drop. Each branch below follows a separate progression track so you can switch between them without missing unlocks.
Step-by-Step Unlock Path
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Clear secret floors 1-3 to claim the free trio (Maze Striker, Lamp Lighter, Hall Monitor). This is the foundation of every Backrooms account, because it gives you a working squad before you spend a single ticket.
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Save 1,000 gems as an emergency pull fund. New players often burn resources on the first banner they see, but waiting for a Hero-rate-up window roughly doubles the expected value of every pull.
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Pull on the active Mythic banner first. Mythic units have shorter pity counters (120 pulls) and the rate-up doubles your odds during the first 24 hours of the banner.
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Switch to the Hero banner when it appears in the rotation. The 200-pull pity for a Hero is steep, so this should be a deliberate decision after you have already secured at least one Mythic.
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Spend duplicate shards on evolution rather than saving them. The damage increase from a tier-2 evolution usually beats holding shards for a future banner.
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Check the re-run slot every four rotations for The Lost Clerk, which remains the strongest HP-anchor in the Backrooms roster.
Players who follow this path can expect to clear most of the Backrooms catalog within 8-10 banner rotations, assuming they pull at least once per cycle, and the math breaks down cleanly when you map each rotation to a concrete milestone: rotations 1-3 secure the Mythic trio (Maze Striker, Lamp Lighter, Hall Monitor) plus the Lamp Lighter evolution tier, rotations 4-6 finish the Hero banner pity track for The Lost Clerk and the HP-anchor slot, and rotations 7-10 mop up event-limited units like the Maze Striker skin re-runs and Holiday Clerk variants that reappear in the same four-rotation window mentioned earlier.
Resource Budget for Full Unlock
| Resource | Required Amount | Typical Source | Time to Accumulate |
|---|---|---|---|
| Gems | ~25,000 | Daily missions, Nightmare mode | 3-4 weeks |
| Summon Tickets | ~600 | Events, codes, AFK rewards | 2-3 weeks |
| Evolution Shards | ~1,500 | Duplicate units, shard dungeons | 4-5 weeks |
| Pity Tokens | 2 (one per Hero banner) | Banner milestones | Built into pulls |
A useful companion for the gem-accumulation step is the Nightmare mode farming guide, which covers the AFK-farming setups that produce the most diamonds per hour during off-hours. Combining that grind with the banner cycle keeps resources topped up without forcing a daily login.
Shiny Variants and Secret Drops
Each Backrooms unit has a "shiny" alternate skin with boosted stats — roughly +15% to every attribute — and a separate color palette. Shinies drop at about 1 in 500 odds during any Backrooms banner pull, regardless of the unit's base rarity. The shiny version shares the same evolution path and shard cost as the standard unit, so the only difference is the stat boost and the visual.
Because the shiny drop rate is fixed and does not benefit from rate-up bonuses, chasing a specific shiny is generally a worse use of tickets than chasing the base unit. Most experienced players treat shinies as a lucky side effect rather than a target.
| Shiny Unit | Stat Boost | Drop Source | Practical Value |
|---|---|---|---|
| Shiny Maze Striker | +15% damage | Any Backrooms banner | High — replaces base unit |
| Shiny Lamp Lighter | +15% burn damage | Any Backrooms banner | Medium — niche use |
| Shiny Hall Monitor | +15% buff radius | Any Backrooms banner | High — biggest stat jump |
| Shiny No-Clip Sentinel | +15% range | Hero banner only | Very high — best in slot |
A shiny No-Clip Sentinel is considered the single most valuable pull in the Backrooms event, because the range increase lets the unit cover lanes that the base version cannot reach. If you are pulling on a Hero banner specifically, treat every shiny drop as a substantial upgrade to your existing squad.
Priority List: Which Backrooms Units to Chase First
Not every unit is worth prioritizing with your limited tickets, especially if you are a free-to-play player. The list below ranks the units by practical impact, based on community-reported usage rates and synergy with the rest of the roster.
| Priority | Unit | Reason | Tickets to Budget |
|---|---|---|---|
| 1 | No-Clip Sentinel (Hero) | Universal placement, no range cap | Up to 200 |
| 2 | Flickering Wraith (Mythic) | Best attack-speed scaler | Up to 120 |
| 3 | Hall Monitor (Support) | Buffs entire squad, free unlock | Already free |
| 4 | The Lost Clerk (Hero) | Frontline HP anchor | Up to 200 |
| 5 | Ceiling Crawler (Mythic) | Splash DPS for grouped enemies | Up to 120 |
| 6 | Maze Striker (DPS) | Free, solid single-target | Already free |
| 7 | Stairwell Phantom (Limited) | Boss-slow niche, only if you have spare pulls | Variable |
If you only have enough tickets to chase one target, No-Clip Sentinel is the most universally useful pull because its placement flexibility means it fits into every team comp. The free units (Maze Striker, Lamp Lighter, Hall Monitor) are listed lower on the priority list simply because they do not require any tickets, but skipping them in favor of a banner is a mistake — clear the secret floors first.
Players who want a broader perspective on hero-rarity units outside the Backrooms event can reference the Hero rarity and unlock conditions guide, which compares Hero-tier units across all of Slop Tower Defense.
Frequently Asked Questions
Are Slop Tower Defense Backrooms units worth pulling if I am free-to-play?
Yes, the free trio is solid and the pity system guarantees every unit within a fixed number of pulls. Save gems for a Hero banner rotation rather than spending on every Mythic, and you can clear most of the roster without spending real money.
How long does each Backrooms banner last?
Each Backrooms banner runs for roughly 72 hours in-game, with an early rate-up window during the first 24 hours that boosts featured unit drop chances by about 2x; banner timers reset on a fixed schedule, so missing one means waiting for a re-run slot or a future rotation, and players tracking the Slop Tower Defense event calendar can pre-allocate gems 12 hours before pull time to avoid burning pity progress on off-banner pulls.
Do limited units ever come back?
Most limited units do not return after their banner closes, with the exception of units that the developer flags for a re-run. Limited units used as evolution fodder for a future Mythic can sometimes be traded in for shards, but this is not a guaranteed path.
Can I unlock every Backrooms unit without spending money?
In practice, no — the combined ticket and gem cost to clear the full roster including limited units exceeds what a free-to-play account can accumulate in a single event cycle. A second event rotation or selective spending is usually required for completion.