Last updated: July 22, 2026

On this page: Quest System · The 12 Class Sets · Part 4 Quests · Hunting Ground Expansions · Medusa · FAQ

MU Online Season 5 – Quest System, Class Sets & Medusa

Season 5 (August 2009) modernized how MU teaches and directs its players — the tabbed quest window, Shadow Phantom soldier quests and the tutorial — and added 12 named class sets that turned classic low-tier armor into serious PvP gear. Part 4 (April 2010) then expanded four hunting grounds with new monster lines and the Medusa world boss. Rebuilt from the original patch notes with the original artwork.

The Quest System Rework

Feature	Details
Quest window (T)	Three tabs — active quests, class-change quests and Castle/Temple info — with descriptions, requirements, rewards, and Open/Abandon buttons for NPC-free quests
Shadow Phantom quests	The buff NPCs in every town (the classic newbie ATK/DEF buff soldiers) now hand out quests through a dialogue window
Tutorial quest	Starts at first login (the flashing Character button) — MU's first real onboarding

The 12 Class Sets

Season 5's signature loot: named sets on classic armor pieces (leather through spirit) with stacking bonuses per piece worn plus a full-set option. They drop as named pieces in the field — cheap to start, brutal when complete, and the backbone of low-level PvP ever since.

Blade Knight / Magic Gladiator

	Set	Pieces	Piece bonuses	Full set
	Anonymous (Leather)	Helm, pants, boots, round shield	2: max HP +50 · 3: AGI +50 · 4: shield DEF +25%	DMG +30
	Mist (Bronze)	Helm, pants, gloves	2: VIT +20 · 3: skill ATK +30	Double DMG +10%, AGI +20
	Berserker (Scale)	All 5 pieces	2–5: max ATK +10/20/30/40	Skill ATK +40, STR +40
	Cloud (Brass)	Helm, pants	—	Crit rate +20%, crit DMG +50
	Rave (Plate)	Helm, armor, pants	2: skill ATK +20 · 3: double DMG +10%	Two-hand DMG +30%, ignore DEF +5%

Soul Master / Magic Gladiator

	Set	Pieces	Piece bonuses	Full set
	Barnake (Pad)	Helm, pants, boots	2: wizardry +10% · 3: ENE +20	Skill ATK +30, max mana +100
	Sylion (Bone)	Helm, armor, gloves, boots	2: double DMG +5% · 3: crit rate +5% · 4: DEF +20	STR/AGI/VIT/ENE +50
	Minet (Sphinx)	Armor, pants, boots	2: ENE +30 · 3: DEF +30	Max mana +100, skill ATK +15

Elf

	Set	Pieces	Piece bonuses	Full set
	Drake (Vine)	Helm, armor, pants, boots	2: AGI +20 · 3: DMG +25 · 4: double DMG +20%	DEF +40, crit rate +10%
	Fase (Silk)	Pants, gloves, boots	2: max HP +100 · 3: max mana +100	DEF +100
	Elvian (Wind)	Pants, boots	2: AGI +30	Ignore DEF +5%
	Karis (Spirit)	Helm, pants, boots	2: skill ATK +15 · 3: double DMG +10%	Crit rate +10%, AGI +40

These live in the same family as ancient sets — smaller bonuses, but obtainable at a fraction of the cost.

Part 4 – New Quest Types

April 2010 added two quest engines on top: random repeatable quests — taken anywhere straight from the quest window, rerolled endlessly for rewards — and event-map quests that trigger extra objectives (and payouts) inside Blood Castle, Devil Square and the other events.

Part 4 – Hunting Ground Expansions

Aida – the Bloody Series

	Monster	Lvl	HP	ATK	DEF
	Bloody Orc	114	117,000	675–710	420
	Bloody Death Rider	115	88,000	795–830	460
	Bloody Golem	117	129,700	715–750	470
	Bloody Witch Queen	120	85,700	835–870	480

Kanturu Ruins – the Warrior Variants

	Monster	Lvl	HP	ATK	DEF
	Berserker Warrior	123	184,370	915–990	543
	Kentauros Warrior	126	198,500	970–1,005	570
	Gigantis Warrior	128	203,000	1,046–1,181	630
	Genocider Warrior	129	218,500	1,240–1,375	715

Swamp of Peace – and Medusa

	Monster	Lvl	HP	ATK	DEF
	Sapi Queen	131	218,000	1,441–2,017	670
	Ice Napin	135	230,000	1,585–2,060	730
	Shadow Master	137	242,000	1,743–2,092	700
	Medusa (boss)	175	7,800,000	7,000–8,000	1,450

Medusa appears at random times in the open swamp fields, leading a pack of minions — no entry ticket, no instance, just a 7.8-million-HP snake queen wandering into your exp spot. Her random spawn made the Swamp of Peace the most contested master-leveling map of the era, and she remains a fixture on every Season 6 server today.

Raklion – the Dark Series

	Monster	Lvl	HP	ATK	DEF
	Dark Mammoth	140	237,000	1,741–2,317	785
	Dark Giant	143	254,000	1,885–2,360	820
	Dark Coolutin	145	248,000	2,043–2,392	850
	Dark Iron Knight	148	265,000	2,217–2,601	860

The Dark series pushed Raklion past its Selupan role into a true endgame grind map — level 140+ monsters with the best exp-per-HP ratios of the classic era.

Continue Reading

Guide	Why it helps
Season 4 guide	Sockets, Raklion and Selupan — the era before.
Ancient sets	The big brothers of the Season 5 class sets.
Leveling guide	Where these expanded maps fit the route.
Class quests	The quest lines the new window organizes.
Season 3 guide	Where the Swamp of Peace story began.

FAQ

Where can I play Season 5?
Browse the Season 5 private servers listed — and every Season 6 server includes all of this content too.

Do the class sets drop everywhere?
They drop as named pieces in regular hunting grounds at their armor tier's level band — check your server's drop settings; many boost them in event rewards.

What does Medusa drop?
High-band excellent and ancient loot on classic settings — comparable to Selupan, but contested in the open field with no player cap.

Why is there no Part 2/3 here?
Korean Season 5 shipped in parts; Parts 2–3 were mostly balance and event passes. The two big content drops — the launch update and Part 4 — are what this guide covers.