A detailed description of Zeromus' script and abilities is available here.
| Zeromus |
| HP | XP | Gil | Boss | Level | Attack Element |
| 61000 | 0 | 0 | true | 96 | None |
| Attack | Accuracy | Defense | M.Def | Speed | Spell Power |
| 174×13 | 99% | 1 | 17 | 69 to 69 | 32 |
| AI |
| Condition 1 | If condition flag is 5 |
| Start a chain |
| Set spell power to 3 |
| Do nothing |
| Chain into |
| Target all characters |
| Cast Meteo on single |
| End chain |
| Wait |
| Do nothing |
| Condition 2 | If condition flag is 4 |
| Do nothing |
| Wait |
| Use [screen Shake Effect] |
| Wait |
| Set spell power to 31 |
| Use Big Bang |
| Wait |
| Use Blk.Hole |
| Show message 118 |
| Wait |
| Set spell power to 14 |
| Cast Nuke on single |
| Wait |
| Do nothing |
| Wait |
| Do nothing |
| Wait |
| Use [screen Shake Effect] |
| Wait |
| Set spell power to 32 |
| Use Big Bang |
| Condition 3 | If condition flag is 3 |
| Do nothing |
| Wait |
| Use [screen Shake Effect] |
| Wait |
| Set spell power to 31 |
| Use Big Bang |
| Wait |
| Use Blk.Hole |
| Show message 118 |
| Wait |
| Do nothing |
| Wait |
| Use [screen Shake Effect] |
| Wait |
| Set spell power to 32 |
| Use Big Bang |
| Wait |
| Set spell power to 36 |
| Target all characters |
| Cast Virus on single |
| Wait |
| Use Blk.Hole |
| Show message 118 |
| Wait |
| Do nothing |
| Wait |
| Use [screen Shake Effect] |
| Wait |
| Set spell power to 32 |
| Use Big Bang |
| Wait |
| Use Blk.Hole |
| Show message 118 |
| Condition 4 | If no condition |
| Use Dummy |
| Wait |
| Use [screen Shake Effect] |
| Wait |
| Use Big Bang |
| Set condition flag to 3 |
| Reaction |
| Condition 1 | If condition flag is 4 and takes damage and self has 12000 HP or less |
| Set condition flag to 5 |
| Do nothing |
| Condition 2 | If condition flag is 3 and takes damage and self has 16000 HP or less |
| Set condition flag to 4 |
| Use Vanish [Restores HP to Full] |
| Condition 3 | If a character uses Call and condition flag is 3 |
| Set spell power to 14 |
| Cast Nuke on single |
| Condition 4 | If a character uses Call |
| Set spell power to 36 |
| Target all characters |
| Cast Virus on single |
| Condition 5 | If a character uses Holy magic |
| Use Weak |
| Condition 6 | If a character uses magic |
| Set spell power to 14 |
| Cast Nuke on single |