Is Elemental Damage From Spell Able To Be Increased?

Example(https://wiki.wynncraft.com/index.php?title=Archer) :
Arrow storm at grade I have +10 % fire damage.

Is there anyway to increase the fire damage?
Example
-By increasing the defense skill point
-From item stats that include +Fire damage

Or is it not?
-The bonus fire damage from defense skill point only increase your weapon fire damage
-The item elemental damage bonus act the same as elemental bonus damage from skill point

 

You can't change that amount gained from the skill, but you can add more damage of that type onto it. It'll do more fire damage if you increase your defense or wear stuff with ids that increase fire damage.
So yeah, you can increase the fire damage like that.