Most spells and items that inflict status effects can fail if the target already has certain other status effects active. This check uses a priority system, where higher priority status effects cause lower priority ones to fail.
Magical and physical attacks have different approaches to status priority, but both are based on the following two bytes, with their status effects listed in decreasing order of priority.
| Status Byte 1 | Status Byte 2 |
|---|---|
| Swoon | Curse |
| Stone | Paralyze |
| Toad | Sleep |
| Small | Charm |
| Pig | Berserk |
| Mute | Gradual Petrification |
| Darkness | |
| Poison |
Magical attacks include all spells, monster abilities, j-items and weapons used as items.
Magical attacks that inflict statuses combine these two bytes into a list, treating the first byte as higher priority1). If the target has any existing status effect with higher priority than the highest priority status of the spell/ability being used, no new status effects will be inflicted.
As an example, Breath inflicts Toad, Mini, Piggy, Silence, Darkness and Charm. The highest priority among these is Toad, so the only status effects that could prevent it are Stone and Swoon. Thus, Breath essentially cannot be prevented with status priority (however, it can be prevented through status immunities2) [TODO: relevant article!]).
Physical attacks include characters attacking with a weapon (rather than using it as an item), as well as monster “punches”.
Physical attacks that inflict statuses combine these two bytes into a list, treating the second byte as higher priority.3) If the target has any existing status effect with higher priority than the one being inflicted, the effect fails.
Physical attacks must also meet certain other requirements to take effect. See: Status Procs.
Poison ignores status priority when being inflicted by magical spells or abilities. In these cases, it can only be prevented with immunity.4)
Gradual Petrification ignores status priority when being inflicted via the monster ability Petrify. It can only be prevented with immunity.
Some multi-target monster abilities may not work as expected, especially -whichburn abilities that are not multi-target in the vanilla game.5)
[TODO: Other exceptions?]