Summoners War - Rune - Rarity

There's 5 different Rune Rarity! Each Rune, when created, will receive a Rarity. Each Rarity give randomly a number of Sub-Stat! Higher is the Rarity the more Sub-Stat it will receive and of course the value of the Rune will raise! Additionally, the Rune change in his Rarity each 3 Power-Up: 3/6/9/12, and will receive randomly a Sub-Stat, but there's a exception, if the Rune is already in the Rarity when it Power-Up, it will instead receive a update in the Sub-Stat already present!

Rarity	Color	Sub-Stats
Common	White	0
Magic	Green	1
Rare	Blue	2
Hero	Purple	3
Legendary	Orange	4

Note: I use Guard Rune Set as example..

Rune Upgrade Example

Here's an example of a Rune Upgrade with a Rune Rarity of Magic to demonstrate the Power-up Bonus Properties of a Sub-Stat:
Power-Up +0 = Brand New Rune!

Name	Mortal Swift Rune (3) - Magic
Slot Stat	DEF +22
Prefix Stat	CRI Rate +5%
Rarity Sub-Stat	Accuracy +8%

Power-Up +1 = 750 Mana Stone

Name	+1 Mortal Swift Rune (3) - Magic
Slot Stat	DEF +30
Prefix Stat	CRI Rate +5%
Rarity Sub-Stat	Accuracy +8%

Power-Up +2 = 1475 Mana Stone

Name	+2 Mortal Swift Rune (3) - Magic
Slot Stat	DEF +38
Prefix Stat	CRI Rate +5%
Rarity Sub-Stat	Accuracy +8%

Now we can see the message: Power-up Bonus Properties
It mean that if we try to Power-Up to +3, we will receive a Sub-Stat! But with that kind of Rune. The Rarity is already at Magic, so the Rune will not chance in Rarity instead of receiving a new Sub-Stat it will Update the current Accuracy Sub-Stat between: +4% to +8% Accuracy (for a Grade 6*)
Power-Up +3 = 2200 Mana Stone

Name	+3 Mortal Swift Rune (3) - Magic
Slot Stat	DEF +46
Prefix Stat	CRI Rate +5%
Rarity Sub-Stat	Accuracy +14%

In this example, I receive +6% Accuracy in the possibility of +4% to +8% Accuracy!