Last updated: September 7, 2026

On this page: Story · Stats & Class Line · The Agility Ladder · Skills From Beads · All Skills · Master Tree · Short Sword Ladder · Early Sets · Set Ladder · Ancient Sets · Wings · How to Play · FAQ · 4th Skill Tree

MU Online Slayer – Skills, Short Swords, Agility & Guide

The Slayer is MU Online’s assassin, and she is gated on Agility more heavily than any class is gated on anything. Demolish needs 1,450 Agility and Pierce Attack needs 1,100 — and her endgame weapon asks for 1,187 Agility against only 354 Strength. She carries no shield, and her master tree is the second smallest in the game at 58 nodes, behind the Gun Crusher’s 56.

How the Slayer Looks at Every Evolution

The base character model at each class change, rendered from the game client’s own player files — no armour equipped, so you can see exactly what the evolution itself changes.

Story

The Slayer does not hold a line; she gets behind it. Everything in her files points the same way — a short curved blade instead of a sword, no shield in any slot, and a skill list built around closing distance, striking and disengaging. Her signature abilities are Bat Flock, Pierce Attack, Detection and Demolish, and each one is locked behind an Agility number rather than a level.

She also learns from Beads — consumable items that teach a skill, the same idea as the Dark Lord’s scrolls and the Rage Fighter’s parchments, but with her own name for it.

Stats & Class Line

Class-quest gates come from Common.ini: 400 for 3rd, 800 for 4th, 1,200 for 5th.

The Agility Ladder – What It Actually Gates

Her skills are not gated on level so much as on Agility, and the numbers get very large:

Her weapons reinforce it. Every mastery short sword asks for far more Agility than Strength:

Skills From Beads

Five of her abilities arrive as consumable Beads rather than from a trainer. All five are flagged Slayer only:

All Slayer Skills – Level, Cost, Range & Role

Pulled directly from the server skill table (Season 21 files), in unlock order: every skill the Slayer line can learn from creation to 5th class, and what it is for. Lv is the character level, Req the stat gate, AG the ability-gauge cost, Range in tiles, CD cooldown (buff duration in brackets). Shared utility (Stun, Swell Mana, Invisibility, the Crywolf spells) and master-tree skills are not repeated here.

Slayer Master Skill Tree

58 nodes — tied with the Illusion Knight for the second smallest master tree in MU Online, behind only the Gun Crusher’s 56. The Rage Fighter has 61, the Rune Wizard 66, the Magic Gladiator 77. Most cap at 20; Sword Inertia Mastery, Bat Flock Mastery, Detection Strengthener, Rush and Short Sword Mastery cap at 10.

Slayer exclusives

Shared blocks

The usual survivability set — three Durability Reduction stages, Defense Increase, Defense Success Rate, Steel Armor, Vengeance, Armor Set Bonus, Maximum Life, Max HP Boost and the SD nodes — plus critical, excellent and double damage rates, ignore-defense chance and SD Absorption.

Slayer 4th Master Skill Tree (Season 20+)

The Season 20 4th skill tree replaced the old passive master tree with skill-specific branches. The Slayer gets 3 branches holding 3 Enhancement Skills — Sword Inertia Mastery, Bat Flock Mastery, Pierce Attack — each built around an Enhancement Skill (a boosted version of the base skill) with link nodes that modify it, a debuff proc (a magic circle that spawns on hit) and passives that upgrade the debuff. Group 4 holds the shared finishing skills Poison Storm, Frozen Slayer, Bloodying Hit. Points come from master levels; every node lists its cap and what it needs unlocked first. Text is the client tooltip with the per-point value shown as N.

Branch 1 – Sword Inertia Mastery

Branch 2 – Bat Flock Mastery

Branch 3 – Pierce Attack

Group 4 – finishing skills

The Short Sword Ladder

Short swords are hers alone — 20 of them. Attack speed climbs from 20 on the starter blade to 45 and then holds there for the entire mastery ladder. Note the Agility column: it never drops below 1,087 once you reach mastery tier.

Before mastery

Early Sets – What to Wear Before 400

Her own armour below the mastery tiers, worn on the character.

Slayer Set Ladder – Every Tier Worn

All twelve mastery tiers composited onto the character from the client’s own model files — ten mastery grades and the two Legendary sets, five pieces each.

The same ladder as numbers, all five slots:

Slayer Ancient Sets

Every ancient set the Slayer can wear, read from the server’s set files. Ancient items look exactly like their base set (an ancient Dragon Helm is still a Dragon Helm), so each card shows the base armour worn. Options unlock one at a time as you equip more pieces of the same set; the full-set bonus needs every piece, including any weapon, shield, ring or pendant that belongs to it.

Ancient items also carry a hidden stat bonus by tier (Tier I +5, Tier II +10 to the set’s stat) and can only be obtained from the Illusion Temple, Blood Castle, Chaos Castle and boss drops.

Wings

The master tree treats them as offensive equipment through Wings of Silence Attack Strengthener, alongside the defensive node.

How to Play the Slayer

Like the Rune Wizard, her stat requirements answer the build question for you — but on Agility rather than Energy.

1. Pure Agility – the only real build

Agility first, and keep going. You need 380 for Bat Flock, 800 for Detection, 1,100 for Pierce Attack and 1,450 for Demolish — plus 1,192 just to hold a Silver Heart Short Sword. Strength gets roughly a third of your Agility and no more; that ratio matches every mastery weapon in her ladder.

2. Stamina-supported assassin

Same Agility floor, but you put the spare points into Stamina rather than Strength. This is the honest answer to having no shield: her only defensive master node is Weapon Block, so health is the mitigation. Pair with Life Absorption and the Defense Success Rate block.

3. Burst opener

Built around Rush, Detection and Demolish — the three utility skills with long cooldowns — and their master nodes. Expensive in points and only pays off in PvP, where opening the fight on your terms is worth more than sustained damage.

FAQ

How much Agility does a Slayer need?

A great deal - Demolish requires 1,450 Agility, Pierce Attack 1,100 and Detection 800, and the Silver Heart Short Sword and above all require 1,192. Only the Elf (1,500 Energy), Rage Fighter (1,480 Vitality) and Grow Lancer (1,470 Agility) have steeper single requirements anywhere in the game.

What is the Slayer's best skill?

Pierce Attack at level 160 - 170 damage at range 6 for 30 mana and 10 AG. It needs 1,100 Agility. Bat Flock is the efficient filler at 90 damage for only 5 AG.

Can the Slayer use a shield?

No. Zero of the game's 127 shields are flagged for her, and her master tree has no shield nodes at all - only Weapon Block. She shares this with the Rage Fighter and nobody else.

Why does Rush cost so much?

Rush costs 200 mana and 200 AG for 178 damage, one of the most expensive single presses in the game behind the White Wizard’s Illusion. It exists to close distance at range 7, not to deal damage. Pressing it as an attack will empty your stamina bar in one action.

How does the Slayer learn skills?

From Beads - consumable items that teach a skill, the same idea as the Dark Lord's scrolls. Sword Inertia, Bat Flock, Detection, Pierce Attack and Demolish all come from beads. Buying the bead unlocks the slot; your Agility decides whether the skill will actually fire.

What weapon does the Slayer use?

Short swords - 20 of them are hers alone. Attack speed reaches 45 and then stays there for the entire mastery ladder, so every tier is a straight damage upgrade with no speed trade-off.

Which short sword should I use before mastery?

The Blessed Arch Absolute Short Sword. It does 260-270 damage for only 203 Strength and 424 Agility, which is more damage than the Bloodangel Short Sword at roughly a quarter of its Agility requirement, and it carries no level gate.

What is the best Slayer weapon?

Imperial Short Sword at level 1,600, 884-975 damage. Worth knowing: from Silver Heart at Mastery 6 onward every short sword needs exactly 359 Strength and 1,192 Agility, so clearing that once unlocks everything up to Lightning.

What stat ratio should a Slayer aim for?

Roughly three Agility for every one Strength. Every mastery short sword in her ladder sits at about a 3.3 to 1 ratio - the Imperial needs 354 Strength against 1,187 Agility. Building to that from early on means never being locked out of your own weapon.

Does the Slayer have one of the smallest master trees?

Almost - at 58 nodes she is second, behind the Gun Crusher’s 56. The Rage Fighter has 61, the Rune Wizard 66, the Dark Lord 67, the Grow Lancer 69 and the Magic Gladiator 77. Her tree is lean in the same way her skill list is.

What is the best Slayer set?

Imperial Slayer at level 1,600 - 2,745 defense across five pieces. Holyangel through Lightning each add exactly 225 defense, eight identical steps in a row, then Lightning to Temple Guard jumps 351.

Is the first mastery set an upgrade?

Yes, but only just. Trace at level 400 gives 363 total defense; Bloodangel Slayer gives 403, a gap of 40 across five pieces. Move for the mastery option slots and the upgrade path rather than the armour value.

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