Tracking down the complete Slop Tower Defense unit collection is the single biggest time sink in the game, because heroes arrive through three parallel systems (summon banners, crafting benches, and fusion altars) and each path gates a different layer of roster growth. This guide breaks down every unit origin, maps each rarity tier to its drop sources, and lays out the crafting and fusion pipelines that turn Common fodder into Hero-grade evolutions. Players who learn the summon and craft rhythm early end up filling their collection roughly two to three times faster than players who rely on summons alone.
According to the official Slop Tower Defense Unit Collection trailer, units are unlocked and added to the player's collection by clearing specific stages, with each stage rewarding a new unit that can then be deployed in subsequent battles.
Three Acquisition Paths Behind Every Unit
Every unit in the Slop Tower Defense unit collection traces back to one of three acquisition paths, and understanding how those paths overlap is the foundation of efficient roster building. Summons pull from a randomized banner pool, crafting recipes convert collected materials into specific units, and fusion altars merge duplicates into higher evolution stages. The table below summarizes how each path feeds the others, which is the first thing any new collector should memorize.
| Acquisition Path | Rarity Range | Currency / Material | Best Use Case |
|---|---|---|---|
| Summon Banner | Common → Mythic | Gems, Tickets | Filling missing slots fast |
| Crafting Bench | Rare → Mythic | Scraps, Souls, Event Tokens | Targeting specific units |
| Fusion Altar | Common → Evolved stages | Duplicate units | Upgrading owned units |
| Event Shop | Event Exclusive | Event Currency | Limited-time roster pieces |
Rarity dictates not just raw power but also how many duplicates you must stockpile before a unit is eligible for its first evolution. Common units need roughly 4 to 6 duplicates for a tier-1 evo, Rare units need 3 to 4, and Mythic units often need only 2 plus a special catalyst. That inverse relationship is intentional: mythic base units are rare pulls, so the developers kept the evo threshold low to prevent dead-banner frustration. A more granular breakdown of which units fall into each rarity band, and which event they belong to, lives in the slop tower defense all units catalog.
Summoning and the Banner Economy
The summon banner is the loudest entry point into the Slop Tower Defense units ecosystem, but it is also the least controllable. Each banner rotation features a boosted rate for two or three featured units, with the remaining slots filled by the permanent pool. Featured units are usually event-tied, meaning they leave the standard banner once their event window closes and reappear only through crafting or future re-runs. According to community data, the average player hits a featured unit roughly once every 60 to 80 pulls, with the pity counter guaranteeing one featured unit at 120 pulls regardless of luck.
Tickets and Gems are the two summon currencies, and they are not interchangeable. Tickets are the limited resource, often handed out through login streaks, events, and codes, while Gems are the soft premium currency that players earn steadily through wave clears and daily missions. Spending Gems on a banner is the right move when a featured unit is critical to a current team comp; otherwise, hoarding Tickets and waiting for a banner that targets a roster gap is the more efficient play. A deeper breakdown of the pity math and banner timing is in the slop tower defense summon rates guide, which complements this collection overview.
Crafting Bench and Material Conversion
Crafting is the deterministic path through the Slop Tower Defense unit collection. Instead of gambling on a banner, players trade specific material bundles for a chosen unit, which makes crafting the safest way to fill a specific roster slot. Each recipe demands a mix of three material families: Unit Scraps (earned by retiring duplicate units), Soul Cores (dropped by named bosses), and Event Tokens (limited to a running event window). The bench cannot craft Common units on its own, because those are already abundant through drops, so the recipes are weighted toward Rare and above.
A practical crafting priority list for new collectors looks like this: first, target one Mythic that fills an unmet role (single-target DPS, splash damage, support buffer, or tank), then move to the next Mythic or a Mythic-adjacent Rare, and only afterward fill in filler slots. Burning materials on a third duplicate of a unit you already own is the most common early mistake, because duplicate conversions are usually worth less than a fresh craft. The slop tower defense tier list is a useful tiebreaker whenever two recipes are competing for the same scrap budget.
Fusion, Evolutions, and Duplicate Management
Fusion is the system that turns the raw count of units you own into measurable roster power. The core rule is simple: feed N duplicates of a base unit into the fusion altar to unlock its next evolution stage, which is typically a stat boost plus a reworked ability kit. Most units have three evolution stages (Evo I, Evo II, and Evo III / Mythic form), and the gap between stages widens as you climb. Evo I is usually a flat damage and health bump, Evo II adds a new passive, and Evo III transforms the unit visually and tactically — in many cases changing the unit from single-target into splash, or from melee into ranged.
The slop tower defense evolutions curve rewards players who plan ahead. Because fusion consumes the base unit itself, you cannot simultaneously hold a unit at Evo I and Evo II, which forces collectors to commit. Players who try to keep every unit at Evo I "just in case" usually stall their progression, because their stockpile of fodder never grows large enough to push any unit to its final form. The single best rule of thumb is to pick one main carry per role, push it to Evo III, and only then start branching into secondary units.
Rarity-to-Evo Threshold Reference
| Base Rarity | Evo I Cost | Evo II Cost | Evo III Cost | Special Reagent |
|---|---|---|---|---|
| Common | 4 dupes | 8 dupes | 12 dupes + 1 Evo Stone | None |
| Rare | 3 dupes | 6 dupes | 9 dupes + 2 Evo Stones | Elemental Core |
| Mythic | 2 dupes | 4 dupes | 6 dupes + 3 Evo Stones | Faction Keystone |
The Evo Stone is the gatekeeper reagent for any final-stage evolution, and it is one of the slowest materials to accumulate. Stones drop from the weekly boss rotation, with roughly one guaranteed drop per clear plus a small chance of an extra. Elemental Cores come from elemental-themed stages, and Faction Keystones are awarded at the end of faction-specific challenge towers. The slop tower defense unit fusion flow therefore has three pacing layers: short-term (duplicates from summons), mid-term (crafting materials for missing units), and long-term (boss and challenge currency for the final evo catalyst).
Why Fusion Matters More Than Raw Collection Size
A common trap among new collectors is to chase 100% collection completion before investing in any single fusion line. The slop tower defense unit collection is large and growing, so chasing completion is essentially a chase of a moving target. Fusion, by contrast, compounds: an Evo III unit on the field can carry an entire late-game wave clear, while a half-built roster of 30 Evo I units will struggle to clear the same content. The ratio of effective power to invested resources is heavily tilted toward fusion, which is why most veteran players recommend pushing one or two lines to Evo III before expanding laterally.
This is also where the slop tower defense best units to craft ranking becomes useful. When you know which crafted units have the strongest Evo III payoffs, you can funnel scraps into those recipes instead of spreading material thinly across the bench. The best crafts in the current meta are usually Mythic bases that unlock a strong splash or support Evo III, because those roles scale hardest into the later wave brackets.
How to Expand Your Collection Efficiently
The fastest collectors treat the three acquisition paths as a single combined pipeline rather than three separate systems. Summons feed duplicates into the fusion altar, the fusion altar outputs stronger units, and stronger units clear harder content, which in turn drops the crafting materials needed to fill the gaps that summons cannot cover. Breaking the pipeline into phases helps prevent burnout and keeps material spending disciplined. The table below captures the four-phase rhythm that most endgame collectors follow.
| Phase | Goal | Primary Action | Expected Roster Size |
|---|---|---|---|
| Phase 1 | First Mythic | Spend Tickets on current banner | 8 to 12 units |
| Phase 2 | First Evo III | Push one fusion line to max | 12 to 18 units |
| Phase 3 | Role Coverage | Craft missing role slots | 18 to 25 units |
| Phase 4 | Event Sweep | Farm event shop + boss rotation | 25+ units |
Phase 1 lasts roughly the first week of play, because the early summon tickets are dense enough to guarantee a featured unit within the pity window. Phase 2 is where the slop tower defense summon and craft balance shifts: you stop pulling as aggressively and start converting surplus units into fusion fodder. Phase 3 is the crafting-heavy stage, and Phase 4 is the steady-state where event content and weekly bosses feed the entire cycle. Players who try to skip Phase 2 and jump straight to Phase 3 usually run out of materials halfway through their craft list, because the fusion fodder was never banked.
Banner vs Crafting: When to Spend
The decision tree for spending resources is short but important. Pull on a banner when one of these conditions is true: a featured unit fills a missing role, the banner is ending within 24 hours and you have pity banked, or a Mythic you have been chasing enters its boosted window. Craft on the bench when one of these is true instead: the unit you need is not on any active banner, you have surplus scraps from retiring low-tier duplicates, or the current event shop offers a material that is normally slow to farm.
The slop tower defense unit collection grows fastest when players alternate between banner pulls and bench sessions rather than committing exclusively to one path. Banner-only players hit a wall once the featured rotation rotates away from their missing pieces, while craft-only players burn through scraps faster than they can replace them. The rhythm that works in practice is two banner sessions per week, with bench sessions filling the gap days.
Event Units and Limited Windows
Event units are the trickiest part of any Slop Tower Defense units collection because they are only available through a specific event window. They typically debut on a banner with a boosted rate, then move to the event shop at a fixed token cost, and finally leave the active pool once the event closes. Returning event units do come back, but usually with a delay of one to two major updates, which means missing an event can lock a unit out of your roster for months. Community data from the Backrooms event suggests roughly 30% of players who skipped the event shop entirely never picked up the limited unit on its return banner.
The right defensive play is to spend event currency on the limited unit first, then on currency-to-material conversions, and only then on cosmetics or resource bundles. Event currency is the most "use it or lose it" resource in the game, because leftover tokens at the end of an event convert to a small generic reward rather than carrying over to the next event.
Advanced Roster Strategies
Once the basics of summoning, crafting, and fusion are in place, the slop tower defense unit collection starts to feel less like a checklist and more like a build decision. The advanced layer involves trade-offs between breadth (many Evo I/II units to swap into a team) and depth (one or two Evo III monsters that dominate a single comp). Both styles are viable, and which one fits you depends on whether you push harder content or play more casually.
Players looking to optimize their roster and master every unit's kit can find a comprehensive visual walkthrough of the Slop Tower Defense Unit Collection showcase, which catalogs each tower's stats, upgrade paths, and unlock conditions.
Breadth Builds
Breadth-focused collectors aim for 20 to 25 units at Evo II, with no single unit pushed past Evo I. The appeal is flexibility: when an event favors a specific element, the player can swap in a counter without grinding fusion materials. Breadth builds also age well, because new units added to the game are immediately usable without a long evo ramp. The downside is that no individual unit hits the stat thresholds needed to clear the hardest single-target bosses, so breadth players usually partner with a friend or clan member who runs a depth build.
| Build Style | Evo Investment | Wave Clear Speed | Boss Clear Speed | Best Content |
|---|---|---|---|---|
| Breadth | Many Evo I/II | Medium | Slow | Events, Daily Runs |
| Depth | Few Evo III | Slow | Fast | Bosses, Endless Mode |
| Hybrid | 2 Evo III + rest Evo II | Fast | Medium | Most Content |
Depth Builds
Depth builds concentrate fusion fodder on one or two units until they hit Evo III. The slop tower defense unit fusion investment pays back hard here, because Evo III units can usually solo the later wave brackets when paired with a single support tower. Depth players typically clear weekly bosses in the first attempt and dominate leaderboard runs, but they struggle when the developers release a new boss with a hard counter to their main carry. The classic fix is to maintain a single alternate carry at Evo II as a backup, which is essentially a small dose of breadth on top of a depth core.
Hybrid Builds and the Meta Answer
Hybrid is where most top players settle, and it matches the long-tail meta more closely than pure depth or breadth. The pattern is two Evo III mains, a handful of Evo II supports, and the rest of the roster at Evo I as a "just in case" bench. The slop tower defense evolutions needed to reach this state are roughly equivalent to two full fusion lines plus the materials to keep a third line parked at Evo II. Players who run this build clear almost all content at expected pace and only struggle during the first few days of a new event, before the banner pool has had time to deliver event-specific duplicates.
Frequently Asked Questions
How long does it take to complete the slop tower defense unit collection?
Full collection is a moving target because the developers add new units every major update, so absolute completion is not realistic. A practical "all current units at Evo I" target typically takes three to four months of active play, while pushing one or two units to Evo III adds another six to eight weeks of focused fusion work.
What is the best way to use duplicate units in Slop Tower Defense?
Feed duplicates into the fusion altar for any unit you plan to keep on your roster, and retire only the units you are certain you will never use. Retired duplicates convert into Unit Scraps that feed the crafting bench, which is a reasonable secondary use, but the power gain from fusion is usually larger per duplicate spent.
Is crafting better than summoning in the long run?
Crafting and summoning serve different roles. Crafting targets a specific unit deterministically, while summoning fills multiple roster slots at once with a chance of featured units. Most players run a roughly 60/40 split, leaning crafting once the early summon backlog is cleared and they know which units they actually need.
How do shiny and event variants fit into the collection?
Shiny variants are cosmetic alternates of existing units, with a small stat bonus and a unique visual. They count toward collection completion but do not have separate evo lines. Event variants are full units with their own rarity and evo path, so they consume the same fusion resources as any standard unit.
What is the fastest path to a Mythic Evo III?
Combine an active banner pull (to secure the base Mythic) with a focused week of boss farming (to bank Evo Stones) and a steady stream of duplicate pulls. Most players hit their first Mythic Evo III within five to six weeks by following that loop, which is also the rhythm reported by community data from the latest ranked season.