> For the complete documentation index, see [llms.txt](https://guides.epicmu.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guides.epicmu.net/epicmu-information/mu-online-5th-skill-tree-guide-ability-enhancement-system.md).
# MU Online 5th Skill Tree Guide – Ability Enhancement System
Hello Adventurers of the Epicmu Universe !!
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After the 5th class change, create an ‘Ability Card’ using ability determination items,
You can further strengthen your character by attaching it to the ‘Ability Enhancement Core’.
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Ability Determination, Ability Enhancement Stone Information
| **Ability Determination** | **Item Description** |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------- |
| [](https://muonline.eu/uploads/monthly_2023_11/Ability-Determination.png.f4bd993236d292994cbdfdd93fa3ec9d.png) | **This item can be obtained by Elites monster, and is a material item required to create skill cards.** |
| **Ability Enhancement Stone** | **Item Description** |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [](https://muonline.eu/uploads/monthly_2023_11/Ability-Enhancement-Stone.png.a05c9bc304a53f95ce8d4b03413bd5ad.png) | **This is an item that can be created through the CM (Chaos Machine). It is necessary to use Ability Determination, and it is a material item necessary to increase the level of an ability card.** |
B) [Skill] Ability card slot and installation settings:
Skill Ability Card Slot
Extra Ability Card
Get Card
Produced through Chaos Goblin (Ability Determination: 50)
Slot open conditions
5th class change completed, level800master treeopenand1 slots blue open; level 850 2 slots blue open level 900 3 slots green open level 950 4 slots green open level 1000 5 slots purple open level 1050 5 slots purple open
Card Loading Conditions
[Skill] Ability cards can be equipped with skills that have been strengthened in the skill enhancement tree, and all enhancement effects and debuffs are maintained.
The same [Skill] ability card can be worn multiple times in 3 slots. When equipped in duplicate, the ‘Skill Attack Power’ stat overlaps. However, additional effects and additional options do not overlap.
① Ability skills can be used when equipped with a [Skill] Ability Card, and can be used when strengthening Skills in the Skill Enhancement Tree.
② All cards can be created using the Chaos Machine located in Noria Map.
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Ability Level Up & Reduce
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You can use the ‘Ability Level Up/Reduce’ function by right-clicking on a card acquired from the Ability Card Book.
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Illustrative picture
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Ability Card Level Up When you acquire additional Ability Cards that you already own, your card holding amount increases, and you can level up the selected Ability Card using additionally acquired cards and the 'Ability Enhancement Stone' item. The number of ‘Ability Cards’ and ‘Ability Enhancement Stones’ required to level up can be checked in the UI. Ability card maximum level Ability cards can be strengthened up to level 5;
