The major difference is they're way more intelligent and deadly. A single Dark Armos possesses the strength of 20 normal Armos.
The main attacks of the Dark Armos are:
1: Dark Rush
The Dark Armos charges at his foes, knocking them down and canceling any attacks or spells in progress. This attack deals a moderate amount of damage.
2: Evil Scream
The Dark Armos lets out a terrifying evil scream, causing one out of four negative status effects to the enemy, like fear, paralysis, petrification or even instant death if the target's HP are below 20%.
3: Thousand Thrusts
The Dark Armos skips one turn, only to attack the target with a devastating barrage of thrusts in the next one.
Dark Armos have the power to control the other normal Armos, making them stronger and faster.
Power Level for Skies of CD-I Legends only.
The Dark Armos's power level oscillates between 2,000 up to 20,000, while the Normal Armos's power level ranges from 500 to 2,500.