Slotbound Upgrade Tree: Gold Priority Between Waves
A practical Slotbound upgrade tree guide: the 11-node Units section, faction nodes, what to buy first, and how gold compounds better than a saved hoard.
Buy small upgrades every wave instead of saving for one big node. Economy first, army second, defence only when a specific wave is killing you. The Units section shows 11 nodes after the launch hotfix, and faction nodes still exist in the tree even though they no longer count toward that total.
Gold in Slotbound has three destinations: spins, items and the upgrade tree. Spins buy material, items buy time, and upgrades buy permanence. The tree is the only one of the three that keeps paying after the wave that bought it, which is why learning its sections is the fastest way to raise your ceiling.
What the tree is
The upgrade tree is a branching structure bought with gold between waves. It is not persistent across runs: like cores and items, it resets. What it does is convert the gold you earn in a run into stats and rules that apply for the rest of that run.
Three practical facts:
- The Units section counts 11 nodes after the 1.0 hotfix, down from 16, because five faction nodes stopped being counted.
- Faction nodes still exist in the tree; they simply live outside the Units tally.
- Origin Seeker asks for thirty purchases, which is the developer telling you the tree rewards volume over precision.
The three sections that matter
Economy
Nodes that raise gold income, reduce spin cost or improve item value. These are always the first buy because they multiply everything else. A run that buys economy in waves 1 to 4 can afford twice as many upgrades by the boss than a run that bought army nodes first.
Buy when: your army is functional and you have waves left to compound.
Army
Nodes that raise the unit cap, unit stats or absorb efficiency. This is where the tree meets the absorb system: a node that improves star gains makes every unit you feed worth more.
Buy when: economy is online and a judgment wave is two or three waves away.
Defence
Nodes that protect lives or improve survivability. These are reactive, and reactive is fine. A defence node bought because you keep losing one heart to the same wave pays for itself immediately.
Buy when: a specific wave is beating you, not before.
Priority order for a normal run
| Phase | Buy | Why |
|---|---|---|
| Waves 1 to 4 | Cheapest economy node available | Compounding needs time |
| Waves 5 to 8 | Unit cap, then summon quality | Convert gold into a wider army |
| Waves 9 to 12 | Star and absorb nodes | Make the carry hit its next threshold |
| Waves 13 to 17 | One defence node if leaking, otherwise army | Survive the spikes |
| Waves 18 to boss | Whatever counters the boss | Targeted beats generic |
This is a default, not a script. The tree is randomised enough that the cheapest node in the right section matters more than the perfect node in the wrong one.
The faction nodes
Five faction nodes exist outside the Units count. They are the tree's commitment mechanism: buying one is a statement that this run belongs to that family.
Buy faction nodes when:
- You have already committed to a family through three or more summons.
- You are chasing Pure Blood or Faction Bond.
- The node's family matches your carry, not just your front line.
Skip them when:
- Your army is mixed and undecided.
- You are still in the first four waves.
- You need cap or economy more.
The faction guide→ covers the pure versus mixed decision in detail.
Why hoarding loses
The math is simple: an upgrade bought at wave 4 applies for sixteen waves, an upgrade bought at wave 18 applies for two. Gold held is gold not working, and Slotbound gives you no interest for holding it.
The one exception is saving for a specific node that unlocks a threshold, such as a cap increase that lets you field the units you already have. Even then, buy the cheap node first and let the expensive one wait a wave.
Where gold competes
| Spend | Return | When it wins |
|---|---|---|
| Upgrade node | Permanent, compounding | Army is at cap, waves remain |
| Bought spin | One unit, immediate | Army is below cap and material is scarce |
| Item | One wave answered | A specific wave is about to kill you |
The comparison is not abstract. The machine header tells you what a spin costs, and the tree tells you what a node costs. Whichever produces more army per gold is the answer this wave, and the answer changes as the run goes on.
Mistakes that cost runs
- Buying a defence node before economy. You survive wave 6 and lose wave 12 because you never scaled.
- Ignoring the cap. An army at cap wastes every line beyond it, and cap nodes are cheap.
- Spending on faction nodes in a mixed run. They do nothing for an army without the family.
- Saving for a big node while leaking lives. A lost heart is permanent; a delayed upgrade is not.
Sources
Official source: Slotbound on Steam ↗
- Steam store page ↗ for the upgrade and core systems.
- Steam news hub ↗ for the hotfix that changed the Units section from 16 to 11 nodes.
- Steam achievement stats ↗ for Origin Seeker, the thirty-purchase achievement.
FAQ
How many nodes are in the Units upgrade section?
Eleven, after the launch hotfix removed five faction nodes from the count. The faction nodes themselves still exist in the tree.
Do upgrades carry over between runs?
No. The tree resets each run, which is why buying early and often beats saving.
Is there a respec?
No respec is documented. Buy nodes you can use now rather than nodes you might need later.
Does the tree ever run out?
The tree is finite for a run, and the Origin Seeker achievement at thirty purchases suggests a full run buys enough nodes to complete a significant portion of it. Past that point, gold belongs in spins and items.