Skill Add-ons refer to the additional effects you can “add-on” to certain skills to aid you greatly in combat.  

Skill Add-ons can be easily applied to your skills if you meet the necessary requirements, and the effects are a must-have for adventurers seeking to improve themselves. 
 
Skill Add-ons require you to be Lv. 50 or higher. 
You can apply up to 6 Skill Add-ons, with each one unlocked at levels 50, 52, 54, 56, 58, and 60. 

How to Apply Skill Add-ons

① Once you’ve reached Lv. 50, head to the nearest Skill Instructor NPC in any major city.

▲ Regardless of their location, these NPCs all offer the same functions. Find one in a major city near you to use the Skill Add-ons function. 

 
② Interact with the NPC, then select “Skill Add-ons" to proceed to the screen displayed below:

③ First, select the skill you wish to “add-on” an effect to. 

▲ It’s most efficient to choose a skill you use regularly in battle, and one that has a short cooldown. 

 
④ Lastly, select the effect you wish to “add-on” to the selected skill. 

▲ You can select up to two different effects, which will activate when the selected skill hits a target. 
 

How to Efficiently Use Skill Add-ons 

First Method 

You cannot stack the same "add-on" effect multiple times on one skill. 
However, you can choose to have the same effect for other skills. 
 
For example, you can’t “add-on” the “Extra Damage to Monsters +20 for 7 sec“ effect to skill (A) twice, but you can add that same effect to both skills (A) and (B). 
 
However, do note that applying the same effect to skills (A) and (B) will not result in an extension of the effect’s duration (i.e., “Extra Damage to Monsters +20 for 14 sec) but will rather re-apply the original effect each time skills (A) and (B) hit a target. 
 
Therefore, you must consider the skills you combo with during battles, 

which Skill Add-on effects will be most important to maintain during combat, 

that you aren’t over-investing wholly in just one single effect, 

and that you’re activating multiple Skill Add-on effects in order to utilize them efficiently. 
 
Second Method 
The types of Skill Add-on effects you can apply to skills are the same, but there are discrepancies in the numerical values applied to certain skills. 
Please refer to the examples below: 

▲ Example 1) Berserker > Skill Add-on effects for "Fearsome Tyrant” 
 

▲ Example 2) Berserker > Skill Add-on effects for "Rock Smash” 
 

As observed above, the numerical values of Skill Add-on effects differ per skill. 
Therefore, it is important to calculate the actual values of the effects applied to the skills used in your combos to make the most efficient use of Skill Add-ons.

Additional Tips for Skill Add-ons! 

 
Skill Add-ons for Ultimate or Prime Skills 

When getting skill add-ons, you would typically get them for the lowest level of the skill. However, if you continue to level up said skill, and learn the additional skills that branch off from it, then the add-on effects will be applied to those additional skills as well. 

▲ As shown above, if you were to get add-ons for “Raging Thunder I”, then "Absolute: Raging Thunder” will also get the add-on effects. 
 

▲ Skill add-on examples 
 

How to Reset Skill Add-ons 
You can change either the skill with the add-ons, or just the add-on effects, by using Memory Fragment x1. 

However, if you have either "Cliff's Skill Add-on Guide" or the "Secret Book of Old Moon” buff active, then you can make as many changes to skill add-ons as you like, without spending any Memory Fragments. 

 
Use Skill Presets to Save Skill Add-ons

Try using the Presets in the Skills window (Hotkey: K). 
Not only does this function allow you to save the skills you’ve learned, it also saves the skill add-on effects as well. 

Another Way to get Skill Add-ons 
Try looking for an Adventurer with the title “Unrivaled” above their head and interact with them.  
They have a special ability that enables other Adventurers to get skill add-ons. 

* The content of the game guide may differ from actual game content, depending on the update and content changes.