Slayer - MU Online Character

The MU Online Slayer is the game's short-sword assassin, added in Season 15: a Lorencia human rebuilt by Kundun into a half bat-demon who throws her blade at range and closes on packs at speed — an assassin that never fully commits to melee. She sits on the creation screen with no unlock condition, she is the only class with her own exclusive muun, and her fourth class is locked to PvP servers.

This guide covers the Slayer end to end: her skills with client-verified names and numbers (including the official name most wikis get wrong), the Desmodus muun nobody else can have, the Slaughterer fourth-class quest line from Cent, the Detection trick that matters more on a private server than an official one, and how she plays on a Season 22 server today.

Who the Slayer is

The lore is a horror story told casually: a human from Lorencia, rebuilt by Kundun into a half bat-demon, who now hunts with thrown short swords and flocks of bats. The kit follows the biography — the element on her own attacks is Darkness, the flock poisons what it touches, and the finisher only lands its full count on poisoned targets. The client's class table confirms her ladder: Slayer, Royal Slayer, Master Slayer, Slaughterer.

One rollout note from the client's own strings: on Webzen's service the Slayer opened on the speed server first and reached regular servers with the season update — the same pattern the Crusader used later. On ours she is simply there from day one.

The skill list, with client-verified numbers

Five slots come straight from the Dark Knight (Twisting Slash, Uppercut, Lunge, Cyclone, Rageful Blow). The class proper is below — names and numbers from the game's own English client data. One correction most wikis get wrong: the blink finisher is officially Pierce Attack, not "Fierce Attack".

Demolish is bought rather than learned: Priest James in Elbeland sells it for Ruud, the only part of the kit gated behind a currency instead of a level. In play the rule is absolute: Bat Flock before Pierce Attack, always — the extra hits only land on a target the flock has already poisoned.

Three more skills sit in the wider kit, and one more on the mount: Rush is the master-tree charge that closes distance and impacts hard; Poison Storm and Bloodying Hit complete the Blasting trio with Frozen Slayer — explosion damage applied to poisoned and bleeding targets respectively; Plasma Storm is Desmodus's own skill, three lightning strikes that also eat the target's armour durability. And two situational ones: Crescent Moon Slash only becomes active inside Castle Siege, and Archangel's Will arrives with an Upgraded Archangel weapon.

Desmodus, the muun nobody else can have

Every Slayer is handed a Special Muun Egg, which hatches Desmodus, a grade 3 muun exclusive to the class. Its base ability lets the muun use attack skills (not in PvP), and its 30-day period ability doubles their speed. The class-change quests grow it for you:

Detection: worth more here than on official

Detection paints every living thing near you onto the mini-map on a 5 second cooldown, and its mastery enhancement pushes the sweep out to 500 tiles. On our Season 22 server, where events and mini-bosses run all day, a 500-tile scan finds spawned bosses, free spots and other players' trains without walking the map — seeing one arrive means getting there first. On a quiet official server it is convenience; on a busy private server it is income.

The set ladder, with drop levels

Her armour ladder runs in named sets, each piece dropping from monsters in a level band — the number below is where the normal version starts dropping, with the Excellent entry level behind it. The five Season 15 sets carry a Slayer from creation into the mid game, and the modern tiers take over from there.

Above Temple Guard sits the Season 21 Imperial tier — and on our Season 22 server the current endgame; see the Season 21 guide for how Legendary and Excellent Imperial work. The short-sword and sword lists get their own pages on the item sites; the set table above is the part that decides where your Slayer can hunt.

The wing ladder, with server numbers

The Slayer's back-slot ladder, read straight from our server's item table — six tiers from 150 to 1200:

Slaughterer: the 4th class change

The Slayer's fourth class is the Slaughterer, opening at level 800 once the third class change is done. All three quests come from Cent (131, 147) in Lorencia, and all three are fights:

After the change, Ctrl + A opens the Slaughterer enhancement tree: each of the three signature skills gets a branch, every branch carries the same seven nodes, and every level-up from 800 on feeds it points. The master tree itself is organised into three named branches — Punishment for defence and recovery, Harsh for the signature-skill strengtheners (Sword Inertia, Bat Flock, Detection, Demolish, plus Weapon Mastery), and Heartless for offence (attack power, critical and Excellent damage rates, the ignore-defence chance). And remember the client's own warning — the Slaughterer lives on PvP servers; a non-PvP server will not connect one.

Above the Slaughterer waits the fifth class, the Rogue Slayer — the Season 19-era 5th class change that unlocks the ability system on this ladder. The class-change quest line runs through Eunice; the Season 19 guide covers what the 5th change does to every class.

How to build a Slayer

Agility is the class — her highest creation stat, and the gate every one of her own skills measures. Strength follows only as far as the skill gates demand; Vitality keeps an assassin alive long enough to blink out. The classic spread for the assassin build is roughly 25% Strength, 50% Agility, 15% Vitality, 10% Energy; a warrior-flavoured spread trades Agility for Strength and Vitality when you want to stand and trade instead of blink. On our server every stat caps at 32,700, so the endgame question is the order you pour in, not where.

Play the Slayer on a live server

The Slayer is live and directly selectable on our Season 22 server — high exp, stats to 32,700, events and mini-bosses all day, and a PvP environment where the Slaughterer tier actually functions.

• Create your account — it takes about a minute
• Download the client, pick the Slayer, and buy your orbs from Alex at (115, 120) in Lorencia
• New to MU Online? Start with how to start — the Summoner guide is her set-party partner if you want the duo story

Every skill on the bar, read from our server's own files

The complete list, pulled straight from the skill table our server runs — level to learn, base damage, mana and AG cost, range, the stat gate, the +1-damage-per-X scaling and the imprint value. If another site disagrees with a number here, ours is the one the server actually uses.

The master skill tree (3rd class), node by node

Unlocked at the third class change (level 400); every level from 400 to 800 grants one point. Three branches, with the node names read from our server's own tree file:

Defense branch: Durability Reduction (1), PvP Defense Rate Increase, Maximum SD increase, Auto Mana Recovery Increase, Durability Reduction (2), SD Recovery Speed Increase, Automatic HP Recovery Increase, Defense Increase, Elemental DEF Increase, Automatic AG Recovery Increase, Durability Reduction (3), Defense Success Rate Increase, Armor Set Bonus Increase, Vengeance, Energy Increase, Stamina Increase, Agility Increase, Strength Increase, Wings of Silence Defense Strengthener, Weapon Block, Wings of Silence Attack Strengthener, Steel Armor

Attack branch: Attack Success Rate Increase, Cyclone Strengthener, Sword Inertia Strengthener, Twisting Slash Strengthener, Anger Blow Strengthener, Sword Inertia Mastery, Maximum Life Increase, Weapon Mastery, Maximum Mana Increase, Bat Flock Strengthener, Maximum AG Increase, Bat Flock Mastery, Max HP Boost, Detection Strengthener, Rush, Demolish Strengthener, Demolish Mastery

Weapon branch: Attack Rate, Short Sword Strengthener, Short Sword Mastery, Mana Reduction, Monster Attack SD Increment, Monster Attack Life Increment, Minimum Attack Power Increase, Monster Attack Mana Increment, Maximum Attack Power Increase, Increases critical damage rate, Restores all Mana, Restores all HP, Life Absorption, Increases excellent damage rate, Battle Mind, Restores all SD, Increases double damage rate, SD Absorption, Increases chance of ignore Def

What each stat point does

The classic MU formulas, with this class's damage stat in the first row. Per-point HP and mana are in the table at the top of the page.

Class specialization and the EXP party

Two systems the stat screen never explains. First, specialization: as the class damage stat climbs past 1,500 and then 2,000, the character earns bonus damage on the same skill set — up to +45% at the top tier. Second, the classic EXP-party combos are Dark Knight + Dark Wizard + Fairy Elf and Dark Lord + Summoner + Magic Gladiator/Rage Fighter — this class belongs to neither, so build parties from the combat trios above.

Ability cards (5th class): Pierce Attack of Saturation.

MU Online Slayer FAQ

What is the Slayer in MU Online?

The Slayer is MU Online's short-sword assassin, added in Season 15: a Lorencia human rebuilt by Kundun into a half bat-demon who throws her blade at range, blinks in for the kill, and returns. Her element is Darkness, her main stat is Agility, and her ladder runs Slayer, Royal Slayer, Master Slayer, Slaughterer.

Which season added the Slayer?

Season 15, as the only class that patch added, together with the Scorched Canyon hunting ground. The season's guide carries the full breakdown.

How do you unlock the Slayer?

There is no unlock: the Slayer is a base class, available by default on the creation screen, starting in Lorencia. On Webzen's official service she opened on the speed server first and regular servers with the season update; on our server she is simply there.

What is the best Slayer build?

Agility above everything — it is her highest starting stat and the gate on every one of her own skills. Strength only as far as the skill gates demand, Vitality to survive the blink. On a server capping stats at 32,700 the order matters early and stops mattering late.

What is the Slayer combo?

Bat Flock before Pierce Attack, always. The flock lands two hits and poisons the target with damage over time; Pierce Attack blinks in for two hits and returns, and on a poisoned target it strikes the weak point for two more. Skipping the flock skips half the finisher.

What is Desmodus?

The grade 3 muun exclusive to the Slayer, hatched from the Special Muun Egg in her starting inventory. It can use attack skills (not in PvP), its 30-day ability doubles their speed, and the class-change quests hand back level 1 Desmodus three times, then a Desmodus Evolution Stone at the fourth.

What is the Slaughterer and how do you get it?

The Slayer's fourth class, opening at level 800 after the third class change, through three fight quests from Cent (131, 147) in Lorencia. It unlocks the Ctrl + A enhancement tree. Note the client's own rule: Slaughterer cannot connect to non-PvP servers.

Where do you buy Slayer skills?

The four base orbs come from the Wandering Merchant Alex at (115, 120) in Lorencia — buy all four before you leave. Demolish is different: Priest James in Elbeland sells it for Ruud, the only skill in the kit gated by currency instead of level.

Is the Slayer good for PvP?

Yes — the kit is a PvP design: blink in, strike inside the Demolish ignore-defence window, blink out. Her fourth class exists only on PvP servers, which tells you who Webzen built her for.

What is the Rogue Slayer?

The Slayer's fifth class, the Season 19-era 5th class change at the top of her ladder (Slayer → Royal Slayer → Master Slayer → Slaughterer → Rogue Slayer). It unlocks the ability system for the class, and its quest line runs through Eunice. On our Season 22 server the full ladder including the Rogue Slayer is live.