Knowing what to upgrade first in Be The Final Boss is the difference between a balanced soul economy and a soul-starved mid-game collapse. Every minion accepts upgrades that boost HP, damage, or ability potency, but only some upgrades are worth spending souls on at any given moment. This minion upgrade priority guide gives you a decision framework, a per-wave upgrade order, and a per-minion upgrade recommendation so you never waste souls on low-impact upgrades. Master the framework and you will out-progress 90% of BOSSes in your first 20 runs.
The framework rests on three questions: Is the minion currently survivable?, Does the upgrade enable a new role?, and Does the upgrade compound with another minion's ability?. If the answer to any is yes, the upgrade is worth spending souls on now. If the answer to all three is no, save your souls for the next minion summon. This sounds simple but is consistently misapplied by new BOSSes, who reflexively upgrade every minion as soon as it unlocks rather than waiting for the upgrade to actually matter.
The Upgrade Decision Framework
Before spending any souls on an upgrade, ask three questions in order. The first question determines whether the upgrade is necessary; the second determines whether it is urgent; the third determines whether it is high-impact. Only after answering all three should you spend the souls. If you skip any question, you risk wasting souls on upgrades that do not pay off until much later.
Question 1: Is the Minion Currently Survivable?
If the minion dies in your current wave composition, no upgrade matters — the minion will be dead before it can use it. The first priority is always survivability, which means HP upgrades. A tank with 10% more damage but 15% less HP is a net loss if the tank dies one wave earlier than expected. Survivability comes first; damage comes second; ability potency comes third.
Question 2: Does the Upgrade Enable a New Role?
If the upgrade unlocks a new role for the minion (turning a single-target minion into AOE, for example), it is high priority. New roles open up new wave compositions that you can handle, which compounds the value of every other minion in your formation. Role-enabling upgrades are worth doing even before survivability upgrades in some cases.
Question 3: Does the Upgrade Compound with Another Minion's Ability?
If the upgrade amplifies another minion's ability (boosting a Brute's slow effect, for example, which compounds with a Mage's spell damage), the upgrade is extremely high priority. Ability-compounding upgrades are the most efficient in the game because they pay off across multiple minions simultaneously. The Sentinel's stun ability is the canonical example — upgrading Sentinel's stun rate boosts the damage of every AOE minion adjacent to it.
| Question | Priority Boost | Example |
|---|---|---|
| Q1: Survivability? | Mandatory before anything else | +15% HP upgrade |
| Q2: New role? | High priority if Q1 is satisfied | Single-target → AOE unlock |
| Q3: Compounding? | Highest priority if Q2 is satisfied | Boost stun rate for AOE minions |
Per-Minion Upgrade Recommendations
The table below ranks every minion in the UPD2 roster by upgrade priority within its role. The "First Upgrade" column is what you should purchase as soon as the minion unlocks; the "Hold For Later" column is what you should save until mid-game. Following this table gives you a reliable upgrade order that works across every wave range.
| Minion | Role | First Upgrade | Hold For Later | Priority Score |
|---|---|---|---|---|
| Brute | Tank | +15% HP | +10% Damage | High |
| Sentinel | Tank | +10% Stun Rate | +15% HP | High |
| Doomfist | Tank | +20% Cleave Damage | +15% HP | Very High |
| Archer | Ranged DPS | +10% Damage | +15% HP | Medium |
| Sniper | Ranged DPS | +15% Crit Damage | +10% Attack Speed | High |
| Mage | Ranged DPS | +15% Spell Damage | +10% Range | High |
| Bomber | AOE | +20% Explosive Damage | +10% Radius | Very High |
| Frost Mage | AOE | +15% Slow Potency | +10% Slow Duration | Very High |
| Lightning | AOE | +25% Chain Damage | +1 Chain Target | Very High |
| Hunter | Burst | +20% Single-Target Damage | +10% Crit | Medium |
| Assassin | Burst | +25% Crit Burst | +15% HP | High |
| Cursed | Burst | +20% Spell Burst on Stun | +10% HP | High |
| Soul Gatherer | Sustain | +20% Soul Generation | +10% HP | Very High |
| Demon | Sustain | +15% Damage Aura Range | +15% Aura Damage | Very High |
| Cleric | Sustain | +20% Heal Potency | +10% Heal Range | High |
Tanks: HP First, Ability Second
The first upgrade for any tank should always be HP, because tanks exist to absorb damage and they cannot do that if they die. The Brute, Sentinel, and Doomfist each take +15% HP as their first upgrade, which extends their survivability by roughly one wave. The second upgrade is ability-specific (stun rate for Sentinel, cleave damage for Doomfist) and is worth pursuing once the HP upgrade pays off.
Ranged DPS: Damage First, Range Second
Ranged DPS minions stay out of harm's way, so HP upgrades are lower priority than damage upgrades. The first upgrade for any ranged DPS should be +10-15% damage, which compounds across every shot. Range upgrades are higher priority than HP for ranged DPS because they extend the safe zone and let the minion shoot heroes from further away.
AOE: Damage and Potency First
AOE minions are high-impact role multipliers, and their upgrades compound with everything around them. The first upgrade for any AOE minion should be the damage stat (Bomber +20%, Frost Mage slow potency +15%, Lightning chain damage +25%). Potency upgrades are higher priority than radius upgrades because potency scales the existing effect rather than expanding it.
Burst: Crit and Single-Target First
Burst minions kill priority heroes, and their upgrades compound with crit mechanics. The first upgrade for any burst minion should be crit-related (Assassin +25% crit burst, Hunter +20% single-target damage). HP upgrades for burst minions are low priority because they are not designed to take damage.
Sustain: Soul Generation First
Sustain minions fuel the rest of your formation, and their soul-generation upgrades pay off across every wave. The first upgrade for any sustain minion should be the soul-generation stat (+20% for Soul Gatherer, +15% aura for Demon). Heal upgrades for Cleric should come second.
Upgrade Priority by Wave Range
The right upgrade priority changes with the wave range because the threat profile shifts. Early game, survivability upgrades on your starting tank are the highest priority. Mid game, damage upgrades on your DPS minions are the focus. Late game, sustain upgrades on your Soul Gatherer are the differentiator.
Early Game (Waves 1-10): Tank HP and Basic Damage
In the early game, your main concerns are surviving the first 10 waves and unlocking the Population skill tree nodes. Spend your upgrade souls on Brute +15% HP first to ensure your starting tank survives the entire early game. After that, spend on Archer +10% Damage to make your DPS more reliable. Hold off on upgrading Sniper until Wave 6 to ensure you actually need it.
| Early Game Upgrade Order | Soul Cost | Cumulative |
|---|---|---|
| Brute +15% HP | 15 | 15 |
| Archer +10% Damage | 12 | 27 |
| Sniper +15% Crit Damage | 25 | 52 |
| Brute +15% HP (second tier) | 25 | 77 |
| Hunter +20% Single-Target Damage | 30 | 107 |
Mid Game (Waves 11-25): DPS and AOE Maxing
In the mid game, your main concern is unlocking the role variety you need for the new heroes. Spend your upgrade souls on Sentinel +10% Stun Rate first to ensure your mid-game frontline can handle the Storm Knight. After that, max out Mage +15% Spell Damage and Bomber +20% Explosive Damage as soon as they unlock, because both are role multipliers.
| Mid Game Upgrade Order | Soul Cost | Cumulative |
|---|---|---|
| Sentinel +10% Stun Rate | 30 | 30 |
| Mage +15% Spell Damage | 50 | 80 |
| Bomber +20% Explosive Damage | 50 | 130 |
| Sentinel +15% HP | 40 | 170 |
| Mage +10% Range | 50 | 220 |
| Frost Mage +15% Slow Potency | 65 | 285 |
| Assassin +25% Crit Burst | 60 | 345 |
Late Game (Waves 25+): Sustain and Role Multipliers
In the late game, your main concern is sustaining the formation through the longer waves. Spend your upgrade souls on Soul Gatherer +20% Soul Generation first to keep your soul economy healthy. After that, max out Demon +15% Damage Aura and Doomfist +20% Cleave Damage for the late-game role multipliers.
| Late Game Upgrade Order | Soul Cost | Cumulative |
|---|---|---|
| Soul Gatherer +20% Soul Generation | 70 | 70 |
| Demon +15% Damage Aura Range | 100 | 170 |
| Doomfist +20% Cleave Damage | 100 | 270 |
| Soul Gatherer +10% HP | 70 | 340 |
| Doomfist +15% HP | 80 | 420 |
| Lightning +25% Chain Damage | 90 | 510 |
| Demon +15% Aura Damage | 100 | 610 |
Upgrade vs Summon Decision
The most common soul-economy mistake is spending souls on upgrades when a new summon would have more impact. The decision rule is simple: summon first if you are missing a role, upgrade first if all roles are filled. Use this rule in every wave, and your formation will grow steadily without starving on souls.
| Situation | Action | Why |
|---|---|---|
| Missing a role entirely | Summon | Role coverage outweighs upgrade power |
| All roles filled, low-HP minion about to die | Upgrade | Survivability keeps formation operational |
| All roles filled, full-HP minion | Save souls | Bank for next wave's spawn |
| Late game, all roles filled | Upgrade | Sustained DPS matters more than new roles |
When Summoning Wins Over Upgrading
Summoning wins when the new minion opens a role your formation is currently missing. The first time you summon a Sentinel, you add the frontline stun role that Brute cannot cover. The first time you summon a Bomber, you add the AOE role that your DPS formation cannot cover. The first time you summon an Assassin, you add the burst role that Hunter cannot cover alone. Each new role multiplies your formation's effectiveness, while each upgrade only adds 10-20% to an existing role.
When Upgrading Wins Over Summoning
Upgrading wins when your existing formation is missing no roles but specific minions are under-performing. If your Mage is dealing low damage because you have not upgraded its spell damage stat, summoning a Sniper alongside it does not fix the Mage's problem. Upgrade the Mage first, then save souls for the Sniper. The "all roles filled, low-impact" diagnosis is the signal to upgrade.
Soul Economy Tracking
The soul economy in Be The Final Boss is roughly: you earn 15-25 souls per wave, plus 50-100 souls per hero kill. A typical Wave 25 run earns 1,500-2,500 souls total. A typical mid-game minion costs 50-150 souls, and a typical late-game minion costs 200-300 souls. Track your soul balance at every wave to avoid running dry at a critical moment.
| Wave | Souls Earned | Typical Spend | Net Balance |
|---|---|---|---|
| Wave 5 | 100-150 | 50-100 (Archer, Sniper) | 50-100 |
| Wave 10 | 200-300 | 100-150 (Sentinel, Hunter) | 100-200 |
| Wave 15 | 300-400 | 200-300 (Mage, Bomber) | 100-200 |
| Wave 20 | 400-500 | 250-350 (Frost Mage, Assassin) | 100-200 |
| Wave 25 | 500-700 | 300-500 (Doomfist, Soul Gatherer) | 100-200 |
Soul Shortage Recovery
If you run out of souls mid-run, the fastest recovery is to sell a non-critical minion (typically a low-tier DPS or a duplicate tank) for 50% of its summon cost. This frees up souls for an emergency summon but costs you formation coverage. The alternative is to bank souls for two waves by skipping upgrades, which lets the natural soul generation catch up. Most BOSSes should never need to sell a minion; proper upgrade priority prevents the soul shortage in the first place.
Soul Generation Boosters
Some events and codes boost soul generation, including the GOLDENTIDE code (which boosts gold rewards) and the UPD2LAUNCH code (which grants instant souls). Use these boosters at the start of a long play session to maximize their value. The Soul Gatherer minion also generates souls on hero kill and is the most reliable soul generation source in the game.
Frequently Asked Questions
Which minion should I upgrade first in Be The Final Boss?
Upgrade your starting Brute tank with +15% HP first, because survivability is the foundation of every formation. After that, follow the per-wave upgrade order from this guide. Skipping the Brute upgrade to chase DPS upgrades is a common mistake that ends runs at Wave 18 when the tank dies.
Should I upgrade or summon new minions in Be The Final Boss?
Summon first if you are missing a role in your current formation. Upgrade first if all roles are filled but a specific minion is under-performing. The decision rule is simple and applies to every wave.
How much do upgrades cost in Be The Final Boss?
Upgrades cost roughly 50% of the original summon cost. A Brute (30 souls) costs 15 souls for its first HP upgrade, while a Mage (100 souls) costs 50 souls for its first spell damage upgrade. Late-game upgrades cost up to 100 souls each.
What is the most cost-efficient upgrade in Be The Final Boss?
The Soul Gatherer +20% Soul Generation upgrade is the most cost-efficient because it pays off across every wave from the moment it is purchased. A 70-soul investment returns 100+ souls over the typical late-game run, which is a 40%+ return on investment.
Can I undo an upgrade in Be The Final Boss?
No. Upgrades are permanent and cannot be refunded. Sell the minion (50% summon cost refund, but 0% upgrade refund) and re-summon it if you need to revert. Plan your upgrade order carefully using this guide before spending souls on upgrades you might regret.