Runes Damage Bonus Proof
Here's some calculations I made on some random items in my inventory.
|Rune Damage||Base Damage||Rune Damage amount of Base Damage||20% of Base Damage|
It's quite clear that all of these damage bonuses are 20% of the weapons base damage rounded to the nearest integer.
Runes on improving weapons
So the basic weapon runes improve physical or elemental damage by about 20%. How does that work with a weapon that improves with level-up? Say the weapon has 30 base damage and I add a rune which adds 6 damage. When I level up to the point that the weapon does 40 base damage, will the rune now add 8 damage, or will it be fixed at the +6 it was when I added it?