MU Online Season 21 Guide

The 2025 – 2026 release, still the game you log into

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This is the least historical guide on the site. Season 21 is the patch directly under the files our server runs, so almost nothing in it has been outscaled: the gear tier you are saving for, the map your endgame happens on, the earring and the mount you upgrade towards, and the cap you are climbing all arrived here. Read it in the order you meet it.

Why this one reads as current content

One version separates Season 21 from Season 22, and a season is not long enough for a gear tier or a hunting ground to go stale. It shipped the Crusader class, a second Legendary tier called Imperial, a hunting ground with an elite zone behind it, the ninth mastery earring, the eighth Guardian, a cap raise to 1,800, a rule change that retuned required stats on every item in the game, and a numbers pass over five class builds.

Season 20 gear is the step you leave behind; Season 21 gear is the step you stand on. The few things it deleted are collected near the end.

Every Season 21 gate on one ladder

Sorted by the level that opens them, the season's features read as a route rather than a release order.

LevelWhat opensWorth stopping for?
2nd class change, Agility 700Focus Shot for the Elf, now an ordinary skill with its orb dropping in the fieldYes, for a drop
1,050Earring of Benevolence, left sideOnly with a +11 Frigid Earring
1,100Earring of Benevolence, right sideSame, and the set option wants both
1,500Rhino, the eighth GuardianYes if your Tauros rolls well
1,650Rakion of OblivionYes. The season's main farm
1,700Rakion of Oblivion with no level penalty, the top event-map grade, the Crusader reward muunYes, three things at once
1,750The Gun Crusher reward muunYes, both stay claimable
1,800Nothing. This is the ceiling—

Everything above 1,650 is one tight band, which is the shape of the season: endgame content with one accessory and one skill fix dangling below it.

The quiet rule change that rewrote every item

A Season 21 Legendary tooltip printing the upgrade stage beside the upgrade level
Level, stage, stars, and the stage bonus split onto its own line.

Start here, because it changes how you spend. An item's upgrade level no longer feeds its required stats. A +15 weapon asks exactly what the same weapon at +0 asks, so parking a weapon at +11 because your build cannot carry +15 is finished. One thing still pushes requirements up, and the same patch made Legendary tooltips stop hiding the rest.

What you are readingSeason 21 behaviour
Upgrade level, 0 to 15Does not raise required stats any more
Jewel of Life optionStill raises required stats while the option is on the item
Upgrade stage, 1 to 5 inside the levelPrinted next to the level in the item name and drawn as a row of stars
Enhancement line coloursRecoloured, so a stage bonus no longer blends into the base stats

The screenshot is a Temple Guard Wand at +15 stage 5: magic +313% as the base line, the stage's additional magic +160 on its own entry. Because the rule changed, every weapon and armour item had its required stats retuned, so anything you memorised in Season 20 is wrong. Read the tooltip.

Rakion of Oblivion is where your endgame happens

The Rakion of Oblivion hunting ground map, the frozen abyss under Raklion
The abyss beneath Raklion, lit by the Aurora of Oblivion.

Raklion froze when the storm of cold answered Seruphan's greed for the Secromicon. Later something stirred underneath it: the Aurora of Oblivion, with the Whale of Oblivion drifting through it. Its light takes your name, your past and everything you loved or hated, and people who wanted an endless war out of their heads walked into the abyss for it. The monsters that followed forgot themselves too. You are there to pull the walkers back out, and after 1,650 this is where you live, so the entry rules matter more than the story.

Getting inDetail
Entry level1,650
Level penalty clears at1,700
Two ways thereThe move command window for 50,000 Zen, or the Raklion entrance at (135, 151)
Ground typeElemental, so MU Helper Plus can drop you at the main or sub-main spot of whichever element you run
Safe zonePresent, and where you land on entry, on death and on reconnect

The residents filter one-dimensional builds. They carry Excellent Damage Rate resistance, Critical Damage Rate resistance, Elemental Critical Damage Rate resistance, Damage Absorption, Debuff Rate resistance and a Shock stat.

What the map pays, and the caps on it

The caps decide how long a session is worth running.

DropPer character, per dayWhat it is for
Bound Ability Crystal4The bulk of the day's income
Bound Imperial Enhancement Stone2Feeds the Imperial tier below
Ability Crystal1The tradable version, one a day
Excellent Imperial armourUncappedThe drop-grade five-piece set, and its only source
Socket necklaceUncappedThe one exception to the socket rule below

Ordinary socket items do not drop here at all. The same patch retuned socket-slot rates in old Raklion and removed the Arca set item drop reward, so this is not the map for sockets.

The three residents, normal and elite

Giant Mammoth, Giant and Iron Knight of Oblivion, the three normal residents
The normal line: three monsters, all level 1,100.
The elite versions of the three Rakion of Oblivion monsters at level 1,110
The same three behind the elite zone flag, ten levels higher.

Three monsters, each appearing twice, so one table covers the whole map.

MonsterNormalEliteExtra typeHow it fights you
Giant Mammoth of Oblivion1,1001,110NukeComes to you and hits in melee range
Giant of Oblivion1,1001,110BoltArea attack
Iron Knight of Oblivion1,1001,110AreaRanged area attack that drains AG and MP from everything it touches

The Iron Knight decides whether you can hold a spot, because AG and MP drain cuts your skills off, not your health. Behind the elite zone flag the same three carry elite skills, an elite debuff option and the boss immunities, Divine Punishment included, and every elite hit applies its debuff at a 100% chance. That is a cost to absorb, not a risk to dodge, and only a Guardian's elite resistance option reduces it.

The five elements, their doors and their debuffs

Your element decides where you walk in and what hits you. The last column is the Guardian resistance that answers it.

ElementElite zone entranceDebuffs every elite hit appliesGuardian resistance type that covers it
Fire221, 219Bleeding, attack power reductionFire
Water238, 44Deadly poison, attack power reductionWater
Earth240, 145Bleeding, attack speed reductionEarth
Wind18, 138Deadly poison, defence reductionWind
Darkness25, 60Bleeding, defence reductionDarkness

The second half of each pair is what hurts: an attack power cut slows your farm, a defence cut kills you. Mismatch your Guardian's roll and you soak all of it.

The weekly elite list, line by line

Elites drop a separate list on a weekly cap. Several are the only source of something, which pays for the debuff tax.

Weekly dropWhat it turns into
Elite Guardian Enhancement StoneThe requirement for pushing any Guardian past +11, Rhino included
Sealed Armour Fragment50 craft one part of Scratched Blood Angel armour, which then makes a +13 Blood Angel piece with no Soul of Blood Angel involved
Elite Option Change Fragment50 make one Elite Option Change Stone
Golden Crest, Garuda's Flame4th wing materials
Uriel's FeatherThe 5th wing relic
Jewel of HarmonyHarmony refining

The Blood Angel line is the one people miss: no Soul of Blood Angel, and you land at +13.

Imperial, the tier you are gearing towards

The Progenitor's Imperial Crusader Legendary set, weapon, shield and armour
Progenitor's Imperial Crusader, the first full Imperial set published.

Imperial is the second Legendary tier, one step above Season 20's Temple Guard, and the ceiling your Season 22 character works towards. Two grades get confused: the crafted Legendary set, published for the Crusader as Progenitor's Imperial Crusader, and Excellent Imperial armour, the five-piece drop version out of Rakion of Oblivion. Side by side, the drop grade is a near miss.

Excellent Imperial armour, the five-piece drop grade of the Season 21 tier
Excellent Imperial: five pieces, roughly 87% of the Legendary defence.
Armour pieceLegendary defenceLegendary required statsExcellent defenceExcellent required stats
Helm655Str 868, Agi 394572Str 863, Agi 389
Armour673Str 1,049, Agi 450590Str 1,044, Agi 445
Pants670Str 943, Agi 413587Str 938, Agi 408
Gloves649Str 781, Agi 369566Str 776, Agi 364
Boots—Not in the published Legendary list560Str 818, Agi 375

Requirements land within five points of each other, so there is no build decision between grades, only defence and rolls. Excellent Imperial takes up to two options from damage reflect 5%, defence success rate +10%, max HP +165, max mana +165, damage decrease 45 and base defence +1.5 per 20 levels. The Legendary weapon and shield roll from a better list.

SlotStatsRequired statsFixed optionRandom options, 1 to 2
Imperial HammerAttack 986 ~ 1,001, attack success rate 413Str 929, Agi 388Excellent damage rate +10%Attack speed +7 · life/8 on kill · mana/8 on kill · attack power +3.6 per 20 levels · attack power +102
Imperial Paladin ShieldDefence 180, defence rate 256Str 817, Agi 321Base defence +3.6 per 20 levelsDamage reflect 5% · defence success rate +10% · max HP +396 · max mana +396 · damage decrease 108

Set bonuses are where Imperial pulls away. Notice how little the first two steps give and how much the fourth does.

Pieces wornWhat switches on
2 armourMastery skill attack power up, Mastery strength up
3 armourDouble damage rate +18%, Mastery attack power up
4 armourMastery critical damage up, Mastery excellent damage up, ignore enemy defence +9%, Mastery all stats up, Mastery base defence up, critical damage rate +20%, excellent damage rate +20%, Triple damage rate +18%, Mastery max HP up, Mastery damage decrease, Mastery ability-skill attack up
All 6, armour plus hammer and shieldExtra Critical rate +5%, Extra Excellent rate +5%, Extra Double Damage rate +3%, Extra Additional Damage rate +4%, and then Nuke +150, Bolt +100, Area +50 attack power on top

Flat attack power across the three extra types ignores your build entirely, and Temple Guard never offered it, so the goal is six pieces.

The Crusader, and why its numbers are missing

The Crusader, the hammer and shield class introduced in Season 21
The Crusader: a hammer in one hand, a paladin shield in the other.

The Crusader is the class Season 21 opened with, and the class Imperial was built out for first: a heavy armoured fighter carrying a hammer and a paladin shield. The gear table above tells you most of it, Strength-led with a serious Agility bill behind it, which puts it in the melee bracket and nowhere near the casters. It also turns up as the level 1,700 reward muun.

One gap, stated plainly: the Part 1-1 patch-note page for the Crusader is missing from the archive this guide was written from, so its base stats, class change ladder and skill list are not here. Everything else comes from the Korean notes. Use the class pages on your own server rather than a number nobody published.

Five class builds, two new power stats

Season 20 gave the Rune Wizard Magic Power (%). Season 21 added Combat Power (%) as the melee counterpart, ran both across five builds, and gave each attack build a signature damage option that scales off its own stats and reads in the character information window.

BuildPower statWhat changedNew optionGrows with
ElfCombat PowerAdded to socket-grade and mastery-grade bows and quiversGale Attack PowerAgility
Illusion KnightCombat PowerAdded to socket-grade and mastery-grade bladesIllusion Attack PowerStrength and Agility
Magic Gladiator, knight buildCombat PowerValues on two-handed swords changedChaos Attack PowerIts own stats
Magic Gladiator, mage buildMagic PowerGains the Magic Power option outright—Energy
Gun CrusherMagic PowerValues changed——
MageMagic PowerValues changed——

There is a price. The Magic Gladiator and the Illusion Knight lost their Skill Attack Power (%) option in exchange, so a build sheet written before this patch overvalues gear carrying it. Seven skills moved alongside.

SkillKind of changeDetail
Focus ShotReclassifiedNow a normal skill without its extra-damage setting; the orb drops in the field. Needs 2nd class change and Agility 700
Poison ArrowDeletedGone from the game
Saturation BladestormBehaviourNo longer dashes when you cast it
Illusion BladeSwappedIts attack power increase became an attack speed increase
Havoc SpearRequirementEnergy 1,326
Ultimate ForceRequirementEnergy 1,250
Bursting FlareRequirementEnergy 1,075

Those three Energy numbers are hard gates, so plan points around them. In the same sweep: item option values and the skill-attack-speed curve were adjusted, attack power, elemental engraving and resource costs changed across the base tree, the skill enhancement tree and the ability tree, the Magic Gladiator's AG gain from Energy was re-derived, and the Blood Angel Magic Two-Handed Sword entered the Ruud shop at 200,000 Ruud.

Two new weapon lines, read as one tier ladder

The ten Magic Gladiator Mastery Magic Staffs from Blood Angel to Lightning
Ten Magic Staffs for the Magic Gladiator, every one at attack speed 30.
The twelve Mage Shields, mastery grades through to Imperial
Twelve Mage Shields, running two grades past the staffs into Imperial.

Two classes got equipment lines of their own, and both use the same tier names, so they read better as one ladder. The Magic Gladiator's Magic Staff stops at Lightning; the Mage's Mage Shield runs through Temple Guard into Imperial, which is why the last two rows fill on one side only.

TierStaff magicStaff magic %Staff required statsShield defenceShield defence rateShield magic %Shield required stats
Blood Angel42 ~ 4452%Str 313, Agi 1072610731%Str 104, Agi 35, Ene 299
Dark Angel53 ~ 5957%Str 327, Agi 1113610940%Str 108, Agi 43, Ene 313
Holy Angel73 ~ 7985%Str 334, Agi 1124611250%Str 109, Agi 45, Ene 340
Soul93 ~ 9994%Str 337, Agi 1125611457%Str 109, Agi 47, Ene 347
Blue Eye105 ~ 115103%Str 340, Agi 1166611763%Str 182, Agi 87, Ene 545
Silver Heart122 ~ 132112%Str 346, Agi 1207611969%Str 186, Agi 91, Ene 557
Manticore140 ~ 150121%Str 346, Agi 1208612275%Str 186, Agi 91, Ene 557
Brilliant158 ~ 168131%Str 346, Agi 1209612482%Str 186, Agi 91, Ene 557
Apocalypse176 ~ 186141%Str 346, Agi 12010612789%Str 186, Agi 91, Ene 557
Lightning191 ~ 201151%Str 346, Agi 12011613096%Str 186, Agi 91, Ene 557
Temple Guard———131196159%Str 186, Agi 91, Ene 557
Imperial———167262210%Str 186, Agi 91, Ene 557

Both lines flatten their requirements at Silver Heart, so holding one tier means holding all of them. The shield's top end is where the value sits: magic% runs 96 to 159 to 210.

The staff line has a catch. The Magic Gladiator can no longer wear the ordinary Mastery Staff, and on the Magic Staff and the Magic Gun the min/max attack power option becomes min/max magic power, with the magic% line applying differently. A conversion ran from 21 April 2026, turning any Mastery Staff from 1st to 10th into a Mastery Magic Staff through Chaos Goblin → Mastery Equipment Crafting → Mastery Equipment Conversion: no materials, 0 Zen, 100%, keeping the upgrade level and every option except the magic value. It is one-way.

Earring of Benevolence, the ninth mastery earring

Both halves of the Earring of Benevolence and the crafting mould
Right half, left half, and the mould that makes either of them.

The two halves are not a matched pair: fifty levels apart, different numbers, different option pools. Decide which side you want first.

Right earringLeft earring
Usable at level1,1001,050
Attack / magic / curse power568 ~ 571528 ~ 531
Elemental defence556498
Rolls, 1 to 3 ofMax mana +1,000 · Excellent damage rate +12% · Critical damage rate +12% · AG auto-recovery +10 · Attack speed +7Max HP +1,000 · Skill attack power +33 · Mastery attack / magic power +163 · Mastery excellent damage +275 · Mastery critical damage +275
Reads asAn offensive-rate and resource earringA mastery-damage earring

Both halves together turn on the set option: ignore enemy defence chance 9%, all stats +12 and mastery damage +110. Mastery values on each side also climb with its enhancement level, up to +15 on crafting stones from the Chaos Goblin.

You do not find one. You upgrade the eighth mastery earring, the Frigid Earring, at +11 or better, and a left makes a left while a right makes a right. Each attempt needs a Benevolence Crafting Mould from Priest James in Elbeland (32, 239) for 25,000 Ruud, plus Jewel of Bless x20, Jewel of Soul x20, Jewel of Chaos x1 and Jewel of Creation x1. The result rolls fresh options, so a well-optioned Frigid Earring carries nothing across.

One ladder for both of this season's upgrades

The earring and the Rhino Guardian use the same rate table, keyed to the base item's upgrade level.

Base item atSuccess rateApplies to
+15100%Frigid Earring → Earring of Benevolence, and Tauros → Rhino
+1490%Both
+1380%Both
+1270%Both
+1160%Both, and the floor; below +11 neither upgrade is offered

Ten points per upgrade level is steep: +11 to +15 buys a 40 point swing, and on the Guardian side that is the cheaper road.

Rhino, the eighth Guardian

Rhino and Rhino Rare, the eighth Guardian mount
Rhino and its Rare colour variant, identical where it counts.

Rhino is the eighth Guardian, a level 1,500 mount equipped from the inventory, and Rhino (Rare) is a low-probability colour variant with identical stats. You make one by upgrading a Tauros at the Lorencia Trainer (122, 110) from +11 or better, on the ladder above.

The Seal of Rhino, the per-attempt material for the eighth Guardian
Seal of Rhino, 50,000 Ruud from Priest James in Elbeland (32, 239).

Every attempt burns Jewel of Bless x20, Jewel of Soul x20, Jewel of Chaos x1, Jewel of Creation x1 and one Seal of Rhino, from the same Priest James, for 50,000 Ruud. Failure eats the sub-materials and knocks the base Guardian back to +0, so the enhancement work goes with the jewels. Success is not pure upside either: it re-rolls your options. A Tauros with three normal options comes back with at least two, and the elite resistance option is always re-rolled.

Option groupWhat Rhino carries
Basic, alwaysMovement speed increase, attack speed +7, defence +476, with defence growing as you enhance it
Normal, 1 to 3 of theseElemental attack +433 · elemental defence +433 · defence +8.0 per 20 levels, to level 1,100 · attack / magic / curse power +8.0 per 20 levels, to level 1,100
Elite resistance, 1 of 5One of the five element types in the Rakion of Oblivion table above, and the only thing that blunts an elite debuff

One real mercy: Guardians can now be dismantled. Unequip one, run dismantle, and you get Guardian Enhancement Stones back, so a spare Tauros is raw material, not dead inventory. Past +11 any Guardian still needs the Elite Guardian Enhancement Stone from the elite zone, which closes the loop back to the farm.

The 1,800 cap and two muuns you can still claim

The Crusader and Gun Crusher reward muuns for levels 1,700 and 1,750
The level 1,700 and 1,750 achievement muuns, both still collectable.

The ceiling moved from 1,750 to 1,800, which turned the old cap into a milestone. Until the next season lands you can claim both achievement rewards, not only the higher one.

MilestoneMuunBase abilityExtra ability, 30 days
Level 1,700Crusader muunElemental defence +1020x the base ability
Level 1,750Gun Crusher muunSkill attack power +1520x the base ability

Both arrive through the Gremory Case with two clocks running: 30 days to collect, then 14 days of validity on the box. Drop the box to turn it into the muun. Miss either window and it is deleted with no restore.

The systems changes you meet every session

Event map grades were rewritten around your level

Entry levels for the graded event maps were redrawn, with monsters balanced against the grade you enter at. Illusion Temple runs a shorter ladder than the rest.

GradeIllusion TempleChaos Castle, Blood Castle, Devil Square, Doppelganger
7—1,700 +
6—1,500 ~ 1,699
51,700 +1,300 ~ 1,499
41,500 ~ 1,6991,100 ~ 1,299
3800 ~ 1,499800 ~ 1,099
2400 ~ 799400 ~ 799
1180 ~ 39950 ~ 399

The columns agree below 800 and diverge above it, and Illusion Temple grade 3 spans 700 levels on its own. On our Season 22 server events and mini-bosses run all day, so your grade is whichever your level puts you in.

Together Boss Raid became an endurance fight

This boss was rebuilt from a burst race into a long one. The direction of each change tells you more than the figure does.

StatBeforeAfterDirection
HP145,690,000700,000,000Nearly 5x
Damage absorption80%90%+10 points
Monster level110115+5
Defence14,60015,000+400
Min attack power36,50032,500Down 11%
Max attack power40,70033,000Down 19%
Min elemental attack6,8404,800Down 30%
Max elemental attack6,8904,900Down 29%

Softer in every damage column, five times the health, ten more points of absorption. Sustained damage beats a spike, and a group that could not survive it before probably can.

Monster Soul Converter levels

Five converter levels, each wanting souls from a different band.

ConverterFrom levelSouls it accepts
Level 51,500 +Devil Sword, Shadow Master of Ruin, Aquila Warrior, Giant Mammoth of Oblivion
Level 41,250 +Crimson Lycan, Underground Persona, Magma Gladiator, Bloody Mutant, Storm Guard, Twisted Crypta
Level 31,150 +Mine Digger, Bahamut of the Abyss, Scorched Warrior, Alquamos of Crimson Flame, Temple Ogre, Ashen Destray
Level 2800 +Feria Knight, Paraka, Cyclops, Skeleton Warrior Captain, Thunder Lich, Swamp Ent
Level 1400 +Destray, Berserker Warrior, Uruk Devil Fairy, Nars Devil Fairy, Dark Mammoth, Sapi Queen

Level 5 is tied to this season: the Giant Mammoth of Oblivion feeds it, so keep those souls.

What Season 21 took away

Every line here is something an older guide will still tell you to do.

  • The Aquilas Temple elite zone is gone, replaced by normal monsters when Rakion of Oblivion's elite zone opened. The same rotation Season 20 ran on Kardamahal.
  • Upgrade level no longer raises required stats. Only the Jewel of Life option does.
  • Poison Arrow was deleted, and Focus Shot stopped being a special skill.
  • Skill Attack Power (%) left the Magic Gladiator and the Illusion Knight, traded for the new options.
  • The Magic Gladiator cannot wear the ordinary Mastery Staff, and the conversion to a Magic Staff is one-way.
  • The Arca set item drop reward was removed, and socket-slot rates in old Raklion were retuned.
  • No ordinary socket items drop in Rakion of Oblivion, the socket necklace excepted.
  • Guardian Angel, Satan and the Horn of Uniria left monster drops and quest rewards in Dungeon, Devias, Lost Tower and Vulcanus, and the Shadow Phantom Unit quest.
  • The Energy Elf's elemental defence buff was re-derived: more from the Energy stat, slightly less from the elemental defence enhancement option.

Everything else here is live. Season 22 builds on top of it rather than replacing it.

What to actually do with Season 21

  • Take gear to +15. Required stats no longer move with upgrade level.
  • Re-read your tooltips once: the stage is printed, and requirements on older items changed.
  • Enter Rakion of Oblivion at 1,650, but aim for 1,700 before you settle in, when the penalty stops and the top event grade opens.
  • Clear the four Bound Ability Crystals and two Bound Imperial Enhancement Stones daily. A missed cap is not made up later.
  • Match your Guardian's elite resistance to the element you farm, and remember the Rhino upgrade re-rolls it.
  • Take a Frigid Earring or Tauros to +15 first. Sixty percent is a bad trade when failure resets the base to +0.
  • Chase all six Imperial pieces. Nuke +150, Bolt +100 and Area +50 only land on the complete set.
  • Claim the 1,700 and 1,750 muuns at the milestone, not when you remember.

Our server runs Season 22 on the latest server files, opens on 30 October 2026, and has high exp, stats capped at 32,700, events and mini-bosses all day, and a custom jewel system. Make an account and start the climb to 1,800.

Season 21, read from a Season 22 server
  • One version below current, so treat these numbers as live gear, not history.
  • Upgrade level stopped raising required stats, and every item was retuned around it.
  • Rakion of Oblivion from 1,650 is the season's farm; its elite zone debuffs you on every hit.
  • Imperial is the second Legendary tier, and only the full six pieces give Nuke +150, Bolt +100 and Area +50.
  • Earring of Benevolence and Rhino share one ladder: +15 is 100%, +11 is 60%, failure resets the base to +0.
  • Cap 1,800, with both the 1,700 Crusader and 1,750 Gun Crusher muuns still claimable.