Disma's moves ignore Evasion and is immune to status effects. It spawns with Faith and Bravery statuses already applied. Disma spawns Dark Lords to come to its aid and will spawn more as his helpers are slain.
Being an undead opponent, Disma is weak against Holy attacks. In the NTSC-U/C version Disma is even harder, because some of its stats are almost doubled.
Excalibur and Holy Lance are effective. It is a good idea to set the healers to heal at a higher percentage than normal. Disma's moves ignore Evasion, so shields are not needed, other than Demon Shield(s) for absorbing Darkga.
The first thing is to cast Dispel to rid Disma of the Faith and Bravery. One strategy is to use Reverse/Decoy and Berserk the person with the strongest weapon. The fight is easier when the Dark Lords are not helping Disma, but when the Dark Lords are killed, Disma will spawn more. To make Disma stop spawning the Dark Lords the player can equip Nihopalaoa and have the character use Chronos Tears on the Dark Lords. If the entire group is stopped, they are out of commission for a long time. Disma itself is immune to all status effects except Oil.
For an easy strategy it is possible to run to the Save Crystal, and Disma will chase the party to the exit. The party can heal and re-buff before going back to keep on fighting (as long as they do not use the Save Crystal for saving). The party can even enter the screen for a moment, get in a few hits, and then retreat back to heal, over and over.
Disma may refer to Saint Dismas. [view·edit·purge]Saint Dismas, one of the two thieves crucified alongside Jesus. While the other thief Gestas was mocked Jesus for not saving the three of them, Dismas was accepting of his justly deserved punishment and asked Jesus to remember him in Heaven.
For his words, Dismas ascended to Heaven upon his death. In many traditions, Dismas was on Jesus's right and Gestas on his left, which is why some depictions of the crucifixion depict Jesus's head tilted to the right, facing Dismas.