Last updated: July 27, 2026

On this page: Requirements · Eligibility Test · New Battle · New Battle 2 · Rewards · FAQ

MU Online 3rd to 4th Class Quest – Full Guide

The 4th class change happens at level 800 and costs no Zen at all. Instead it is three straight fights in an instanced arena against Sent, the NPC who sends you in. Finish it and you unlock the Skill Enhancement Tree.

The NPCs You’ll Meet

Rendered from the game client so you know exactly who to look for.

Requirements

Requirement	Value
Character level	800
Quest NPC	Sent — Lorencia (131, 147)
Prerequisite	3rd class change completed
Zen cost	None
Total stat points	+100
Where	Instanced Area of Eligibility → Test Area

You can enter the staging area from around level 750 to help a partied friend, but you only get quest credit at 800. Talk to Sent to enter the Area of Eligibility, form your party there, then talk to her again to move everyone into the Test Area.

Naming note: the NPC is Sent on official clients. Many server files and guides spell her Cent — same character.

Stage 1 – Eligibility Test

Detail	Value
Objective	Defeat Sent ×1
Her stats	Combat level ~160 · 1,000,000 HP
Reward	+20 stat points

A straight damage check. If your gear is anywhere near level 800 standard this is the easy stage.

Stage 2 – New Battle

Survive in the arena while clearing three Deep Dungeon spawns:

Monster	Kills needed
Deep Dungeon Skeleton Warrior	5
Deep Dungeon Cyclops	5
Deep Dungeon Larva	5

These are summoned copies inside the arena, not a trip to the real Deep Dungeon map. There is a survival timer — 5 minutes on current clients, 1 minute on older ones, so check your server.

Reward: +30 stat points.

Stage 3 – New Battle (2)

Detail	Value
Objective	Defeat Sent again — much harder
Her mechanics	Teleports around the arena and summons one of each Deep Dungeon monster to fight alongside her.
Reward	+50 stat points, Scroll of Gray Oblivion ×1, class evolution, Skill Enhancement Tree

The teleporting is what catches people out — melee characters lose uptime chasing her while the adds pile on. Kill the summons first if your damage is single-target.

The Scroll of Gray Oblivion is delivered to your Gremory Case and expires in 7 days. Claim it immediately.

Class Evolution

3rd Class	Becomes
Blade Master	Dragon Knight
Grand Master	Soul Wizard
High Elf	Noble Elf
Dimension Master	Dimension Summoner
Duel Master	Magic Knight
Lord Emperor	Empire Lord
Fist Master	Fist Blazer
Mirage Lancer	Shining Lancer
Master Slayer	Slaughterer

After this the only step left is the 5th class change at level 1,200.

Continue Reading

Guide	Why it helps
5th class change	The next and final class step at level 1,200.
2nd to 3rd class	The prerequisite chain.
4th level wings	Wings unlocked by 4th class.
Master skill tree	How the skill trees stack.

FAQ

What level is the 4th class quest in MU Online?
Level 800. Talk to Sent in Lorencia at (131, 147). You can enter the staging area from about 750 to help a party, but credit needs 800.

How much does the 4th class change cost?
Nothing. Unlike the 2nd and 3rd class quests there is no Zen fee — it is purely three fights.

Can I do the 4th class quest solo?
Yes, but stage 3 is much easier in a party. Sent teleports around and summons Deep Dungeon monsters, so solo characters lose a lot of damage uptime.

What do you get from the 4th class change?
+100 stat points in total, your 4th class evolution, a Scroll of Gray Oblivion, and the Skill Enhancement Tree (Ctrl+A).