Last updated: July 27, 2026

On this page: What You Unlock · Requirements · The Three Trials · Extra Damage · The Giant Mount · What to Do Next · FAQ

MU Online 5th Class Change – Full Quest Guide

The 5th class change arrived in Season 19 and is the biggest progression gate in modern MU. Unlike the 3rd and 4th changes it gives no new class title — instead it unlocks the entire Extra Damage system, the Ability Enhancement Core, 200 stat points and the exclusive Giant mount.

What You Unlock

Reward	Detail
Extra Damage	A new damage type in three flavours — Nuke, Bolt and Wide — that fires from your enhanced and ability skills
Ability Enhancement Core	The 5th-class card system (Ctrl+J) with Extra, Skill, Option and Elite card slots
200 stat points	Awarded on completing the third trial
3 Extra Ability Cards	Nuke, Bolt and Wide — you must equip one for Extra Damage to work at all
Giant mount quest	Unlocks the exclusive 5th-class mount
Legendary gear access	All Legendary equipment requires the 5th class change

Requirements

Unis — Devias 1 (193, 12)	Level: 1,200+ NPC: Unis — Devias 1 (193, 12) Prerequisite: 4th class change completed Who is Unis? A Guardian Knight serving Lugard, elder sister of Sent of the 12 Priests of Light, and a master of the great scythe. After Kundun's chaos produced monsters with unfamiliar power, research yielded a new force called Extra Damage — and Unis was sent to teach it.

Area	How to enter
Space of Qualification	The preparation area — entered from Unis in Devias. Party up here.
Space of Trial	Entered from Unis inside the Space of Qualification. If you're in a party, one member applying moves everyone in.

The Three Trials

Each trial is a one-minute duel with Unis while Burning Kethotum monsters spawn alongside her. You receive the matching Extra Damage buff before each fight:

Trial	Clear condition	Reward
1st — Nuke	Take the Extra Nuke Damage buff and defeat Unis within 1 minute	Unlocks trial 2
2nd — Bolt	Take the Extra Bolt Damage buff and defeat Unis within 1 minute	Unlocks trial 3
3rd — Wide	Take the Extra Wide Damage buff and defeat Unis within 1 minute	5th class change + 200 stat points + Ability Core + 3 Extra Cards + Giant quest

The gate is damage, not difficulty. One minute is tight — bring enough gear to burst Unis down inside the timer. Partying helps, since the whole party enters together.

Extra Damage Explained

Nuke	Bolt	Wide

Extra Damage fires when you use enhanced skills (from the 4th-class Skill Enhancement Tree) and ability skills (from the 5th-class cards). Each type has its own hit effect and damage-number colours:

Type	Targets	Damage grade	Best for
Nuke	1 target	High	Bosses and single-target burst
Bolt	Up to 2 targets	Medium	Balanced play
Wide	Up to 10 targets	Low	Farming and crowd clear

Critical: you must equip one of the three Extra Ability Cards in the Ability Enhancement Core, or Extra Damage does not fire at all. Extra Damage Defense was added alongside it to reduce incoming Extra Damage — both values show in the character info window.

The Giant Mount

The three Giant types — you receive one at random

Step	Task
Mount quest 1	Hand 300 Jewels of Creation to Unis
Mount quest 2	Defeat Unis while riding a Giant within 1 minute
Reward	A Giant mount — 1 random type of 3

Mount and dismount with the on-screen button or Ctrl+X. It grants a movement speed increase and cannot be ridden alongside other mounts (Muun, Guardian, Fenrir).

What to Do After 5th Class

Priority	Why
1. Equip an Extra Ability Card	Without it, Extra Damage does nothing. Pick Wide for farming or Nuke for bosses.
2. Farm Ability Crystals	Daily cap is 1 crystal + 4 bound crystals per character, so start immediately. They drop in Burning Kethotum-grade maps and above.
3. Fill [Option] card slots	Cheapest cards at 5 crystals each, and they always help. You get 5 slots at 5th class, +5 every 50 levels.
4. Keep Option cards level-even	The [Elite] card level you can mount equals the lowest level among your 5 Option cards.
5. Save for a [Skill] card	50 crystals each — the most expensive but they grant a whole sub-skill.
6. Chase the 5th wings	Over 2,000 attack and defense at +15 — the biggest single power jump available.

Note that Skill Enhancement Tree points can no longer be gained above character level 1,600 — the Ability Core takes over from there.

Continue Reading

Guide	Why it helps
Season 19 guide	Where the 5th class change was introduced.
Ability Cards guide	The card system you unlock.
5th wings guide	Your next power spike after 5th class.
Legendary gear	Requires the 5th class change.

FAQ

What level do I need for the 5th class change?
Level 1,200, with the 4th class change already done. Speak to Unis in Devias 1 (193, 12).

Does the 5th class change give a new class name?
No. Unlike the 3rd and 4th changes there are no new class titles — it's a single generic progression for every class that unlocks Extra Damage, the Ability Core, 200 stat points and the Giant mount.

Why isn't my Extra Damage working?
You almost certainly haven't equipped an Extra Ability Card in the Ability Enhancement Core. Completing the trials gives you all three (Nuke, Bolt, Wide) but you must mount one for the damage to fire.

Can I do the trials in a party?
Yes — when one member applies to enter the Space of Trial, the whole party is moved in. Given the one-minute timer, that's often the easiest way to clear it.