White Knights continue to use Slash Blast for mobbing, it always deals exactly half of Power Strike's damage(cheap maplestory mesos), on a mob of up to 6. Therefore:
With Lightning Charge - 162.5% per target.
Fire Charge (on fire weak) - 234% per target.
Ice Charge (on ice weak) - 204.75% per target.
Lightning Charge (on lightning weak) - 243.75% per target.
They can also use Charged Blow, which deals base 250% damage to each monster in a mob, and stuns them. In exchange, you lose your elemental charge and have to use it again. We provide Maplestory powerleveling for you here.
With Lightning Charge - 312.5% on up to 6.
Fire Charge (on fire weak) - 450%.
Ice Charge (on ice weak) - 393.75%.
Lightning Charge (on lightning weak) - 468.75%.
Unfortunately, due to Slash Blast and Charge Blow being their only arsenal for mobs. They do the least damage overtime to mobs of 5-6 Monsters. Only in 4th job will WKs truly shine, being able to spam Charge Blow. FA hinders this also as explained under the Crusader Section "Damage on Mobs." But until then, they remain a great soloer on overall damage to single targets that are elementally weak. Have a good time in Maplestory.