Slotbound Absorb Guide: Feeding Order and Star Scaling
How absorbing works in Slotbound: the feeding order that builds a carry, when to promote, why faction purity matters, and how to avoid feeding your front line.
Absorb is Slotbound's only real progression system. Pick one carrier, lock it, and feed every spare unit into it until the stars stop coming cheaply. Feed duplicates first, feed damaged bodies second, and never feed a unit that is currently holding a lane in front of your carry.
Every roguelike has a power curve. Slotbound's is unusual because you do not spend currency to climb it, you spend units. The store description says it plainly: summon units, then grow your army by absorbing others. That one sentence is the entire meta, and everything that goes wrong in a run can usually be traced to a feeding decision made three waves earlier.
What absorption does
Absorbing merges one unit into another. The survivor gains progression toward its next star, and the consumed unit is gone. The interface exposes it as a mode rather than a click: the 0.3.0 update added the A-key absorb mode and the manual lock.
Two consequences follow:
- Every unit is either a body or a battery. There is no bench, no reserve, no sell button. A unit you are not using is food.
- Stars are concentrated power. Three stars on one unit is worth more than three units at one star, because the star multiplier applies to a single stat pool that your carry actually uses.
The star ladder itself is confirmed by the Three Stars achievement, which asks you to raise one unit to three stars and sits at 78 percent global unlock. Stars are not a late-game system; they are the first hour.
The feeding order
Feeding order matters because the amount of progression a unit provides is not uniform, and because the cost of a mistake is permanent for the run.
- Lock your carrier. Before you feed anything, put the manual lock on the unit you intend to keep. This is the single most important input in the game, because an unlocked carry is one misclick away from being eaten.
- Feed duplicates of the same class. Same-class material supports the branch you are already on instead of pulling the unit in a direction you did not choose.
- Feed damaged and off-role units next. A wounded shield that already lost its lane is pure material.
- Feed low-rarity bodies before high-rarity ones. A Normal-grade unit is worth more as stars on your carry than as a body on the field.
- Stop when the next star costs two units and a wave. If the remaining path to the next threshold is longer than the waves you have left, redirect material to a second carry.
Promotion and branching classes
On the way up the star ladder the unit is offered a class promotion, and the choice branches. The launch hotfixes fixed a bug where the promotion card showed stat arrows incorrectly, which tells you two things: the card is meant to be read carefully, and the numbers on it are meaningful enough that a display bug was worth hotfixing on day two.
How to choose a branch:
| Your situation | Branch priority |
|---|---|
| Carry is safe behind two bodies | Damage or scaling branch |
| Carry is the front line because nothing else survives | Defensive branch, then fix the front line |
| Run is losing lives to one wave type | The branch that counters that wave type |
| You are chasing a single-family achievement | The branch inside your chosen family, even if the numbers look worse |
The last row is a real trade. Pure Blood asks for the final boss on Hard with single-faction units, and Devourer of All asks for one unit that has absorbed all six families. Those two achievements pull in opposite directions, which is a good sign that the developers intend faction choice to be a real commitment rather than a cosmetic label.
Manual lock is a weapon, not a safety rail
Most players use manual lock once, to protect their carry, and never think about it again. The better use is to lock material you are saving.
If you have a duplicate with excellent rolls and a wave to survive before it becomes food, lock it. If you have a unit you want to promote after the next spin, lock it. The mode persists, so unlocking is one click, and the cost of forgetting to unlock is a unit that never gets absorbed into the carry you wanted to feed.
When to start a second carrier
One carry cannot cover two lanes. Start a second when one of these is true:
- Your army is at cap and your carry is three stars. Extra bodies have nowhere to go, so convert the overflow into a second star stack.
- Your carry is a ranged unit and the wave spawns fast flankers. You need a body that survives contact, and that body should be a carry in its own right.
- A faction synergy is one unit away from activating. A second unit of the right family can be worth more than another star on the first.
Never start a second carrier before the first one has reached the point where the next star is expensive. Two half-fed units lose to one fed unit in almost every wave.
What absorb interacts with
Absorption is not an isolated system. It touches:
- Factions. Feeding a unit of another family into your carry is how a mixed-family carry happens, which is why Devourer of All is possible at all. The faction guide→ covers the six families and the synergy tiers.
- Imprints. Imprints are engraved onto a unit, and an imprinted unit is a unit you do not want to feed away. Read the imprint guide→ before you start engraving.
- Awakening. The 0.4.0 awakening system sits on top of the star ladder, so a unit that is worth awakening is a unit worth protecting from your own cleanup.
- The army cap. Absorption is how you deal with overflow when the board summons more than your cap allows.
The three mistakes that end runs
- Feeding the front line. The unit holding the lane is the unit that keeps your carry alive. Feeding it gains one star and loses the run.
- Spreading stars. Five one-star units look like an army and behave like sandbags. Concentrate first, diversify only when concentration stops paying.
- Feeding before locking. A single absorb sweep without a lock can eat the carry, and there is no undo.
Sources
Official source: Slotbound on Steam ↗
- Steam store page ↗ for the absorb, branching class and random stat description.
- Steam news hub ↗ for the 0.3.0 absorb mode, manual lock and save changes.
- Steam achievement stats ↗ for Three Stars, Devourer of All, Friends to the End and Pure Blood.
FAQ
Can I undo an absorb?
No. Absorption is permanent for the run, which is why manual lock exists and why it should be your first action every wave.
Does the absorbed unit's rarity matter?
Rarity affects the body's baseline stats, so a high-rarity unit is worth more as a body than as material unless it is off-role or badly rolled. Feed Normal-grade units first and keep legendaries alive.
How many stars can a unit reach?
Three stars is the threshold the achievement system uses, and the King's Army achievement asks for five units at three stars, so three stars is a normal endgame state rather than a cap. Higher tiers exist through awakening.
Should I absorb during a wave?
Absorption is a preparation action. Do it between waves, when you can see the board, the cap and the next wave number at the same time.