Passive skills are the difference between a Pal that works and a Pal that carries your team. Breeding is the only reliable way to put the right four on one Pal, so it pays to know exactly how the game picks them. The numbers below come from data-mined breeding settings documented by the open-source Pal Calc project, and they match what players see in practice in 1.0.
Step 1: the parents' passives are pooled
The game takes both parents' passive lists and removes duplicates. If the father has Legend and Ferocious, and the mother has Legend and Musclehead, the pool is Legend, Ferocious, Musclehead (three, not four).
Step 2: how many the child inherits
The child then tries to inherit a number of passives from that pool:
| Passives inherited | Chance (normal Cake) |
|---|---|
| 1 | 40% |
| 2 | 30% |
| 3 | 20% |
| 4 | 10% |
It can't take more than the pool holds, and it always takes at least one if either parent has any. Which ones it takes from the pool is random.
Special Cake (Tech Level 74) overrides this roll to the maximum: the child tries to take four. With a pool of exactly your four target passives, that removes the worst odds in the whole process.
Step 3: random passives on top
Next, the game may add random passives from the general pool:
| Random passives added | Chance |
|---|---|
| 0 | 40% |
| 1 | 30% |
| 2 | 20% |
| 3 | 10% |
A Pal still ends with at most four. Random passives can be good, useless or negative (Brittle, Slacker, Coward…), which is the main reason a "perfect" child takes many eggs.
What this means in practice
- Clean parents are everything. If both parents carry only passives you want, every inherited passive is a good one. One unwanted passive in the pool can be picked instead of a wanted one.
- Merge two-passive lines. A common route: breed a Pal with passives A+B and another with C+D, then cross them. With Special Cake the child tries for all four; you still need the random roll to add nothing.
- Species doesn't matter for passives. You can carry Legend or Lucky through cheap Pals and only switch to your target species in the last step. Just remember the species of the final child comes from its two parents' breeding power.
- Gender is a hidden cost. You need one male and one female at each step, so a good Pal of the wrong gender means another generation (or a trip to the Pal Surgery Table).
- Active skills are separate. Since 1.0, inherited active skills come only from the three skills each parent has equipped, so set those before breeding.
A clean route to a four-passive combat Pal
- Catch or breed a Pal with Legend (legendary Pals can have it) and one with Lucky (a rare wild roll).
- Get Ferocious and Musclehead (or Demon God) on other Pals. Common passives such as Musclehead can also be implanted at the Surgery Table.
- Breed to get one parent with exactly Legend + Lucky and another with exactly Ferocious + Musclehead. Discard any child with extra passives.
- Cross them on a Special Cake. Keep the child that has all four and nothing else.
- If the species isn't right yet, breed the finished passive set into the target species. Clean four-passive parents on Special Cake pass the full set forward.
Plan the route with our breeding calculator and the passive skills list, and read the surgery table guide for when implants beat breeding.
Mutations add a twist
A mutated egg (a 1.0 mechanic) hatches with at least one mutation-only rainbow passive in its first slot, which you can then breed into other lines. See the mutation guide.