Hero roles and Birth Rank in Bomb Farm
Updated 2026-08-31
On this page
In Bomb Farm, Birth Rank measures a hero's natural attributes within that hero's rarity. It is permanent. Leveling, adding stars, equipping gear, using Forge upgrades, or allocating points will not change the letter.
The developer explained this system in the August 30 update. Each natural attribute is evaluated against the range for its rarity, and those evaluations are averaged to determine the rank. A Common S is therefore not automatically stronger than a Mythic E.
What E through S means
| Birth Rank | Natural-attribute quality band | Frequency listed by the developer |
|---|---|---|
| E | 0%–20% | 20% |
| D | 20%–40% | 20% |
| C | 40%–60% | 20% |
| B | 60%–80% | 20% |
| A | 80%–90% | 10% |
| S | 90%–100% | 10% |
The rank chances are the same for all rarities. The percentages describe Birth Rank; they are not damage bonuses, critical-hit chances, or the odds of obtaining a particular rarity.
Compare rarity first, then the hero
When choosing between two heroes, start with their rarity and actual attributes. Use Birth Rank as a way to judge the natural roll within a rarity, then inspect abilities and the equipment each hero would wear.
A higher letter is a useful clue when comparing similar heroes, but it does not replace the rest of the card. The natural-attribute average can hide differences that matter to your intended role, and it tells you nothing about which ability your team needs.
Roles and abilities are separate decisions
The Steam store names four roles: Attacker, Support, Collector, and Specialist. It also lists 20 hero abilities, with ten upgrade levels for each ability.
For a progression squad, begin by checking what is preventing the current group from advancing. If rocks take too long to break, compare the damage-related attributes and abilities of your available heroes. If the group stops working too soon, inspect the condition of the team and its recovery options. Read an ability's description to see whom it affects before spending points.
Do not spend upgrades trying to turn a B into an A. Those upgrades can improve the hero, but Birth Rank stays B.
Stars improve the hero you already own
The Star Ritual upgrades an existing hero; hero fusion creates a new one. This distinction also matters for trading: the August 30 change to fusion does not make the Star Ritual clear a hero's Soulbound status.
If you are deciding whether to use a hero as a material, first check the abilities and equipment you would lose from your working team. Equipment and Rituals separates the different upgrade actions.
Sources: August 30 developer explanation of Birth Rank; Steam store.