Glossary
MU slang translated, in alphabetical order, with what each term means on this server.
Updated on August 10, 2026MU has twenty years of vocabulary of its own, almost all of it abbreviated. This page exists so you can follow the chat without having to ask. Where Zaikan does it differently from the original MU, the line says so.
The table
| Term | What it is | Where to read more |
|---|---|---|
| AG | Ability Gauge, the purple bar under your mana. Several skills consume AG on top of mana. It regenerates on its own anywhere. | HP, MP, SD and AG |
| Anc / ancient | An ancient item, part of a special set. It has a rarity floor of rare, so it shows up with a blue outline, and it lights up bonuses when you gather the pieces of the same set. | Ancient sets |
| BC | Blood Castle. An eight level event, split by level range, twenty minutes long and with no entry fee. | Blood Castle |
| Buff | A temporary strengthening applied to you or to your party. It shows up as an icon at the top of the screen, with the same art as the skill that applied it. | Buffs |
| CC | Chaos Castle. Everyone against everyone, with the floor disappearing. Seven levels, up to seventy players, ten minutes, and a zen entry fee that goes from 25,000 at level 1 to 1,000,000 at level 7. | Chaos Castle |
| Chaos | Two different things: the Jewel of Chaos, a jewel used in nearly every recipe, and the Chaos Machine, the Chaos Goblin machine where items are combined. | Chaos Machine |
| Debuff | The opposite of a buff: a negative effect applied to the enemy, like slow, poison or reduced defense. | Buffs |
| DG | Doppelganger, the four room event with your clone. Its maps were imported, but the event does not run today. | Doppelganger |
| DS | Devil Square. A closed arena with seven levels, split by level range, twenty minutes each. | Devil Square |
| Exc / excellent | An item with special options, the most sought after in the game. Each option raises the rarity one step: one option turns the item green, four turn it gold. It drops at 0.01% and only from monsters level 76 or higher. | Item options |
| GS / gear score | The rating of your gear, adding up tier, refining, excellent, luck, ancient and sockets on each piece. It goes up to around 3,000 on a character and 270 on a single item. | Rarity and Gear Score |
| Harmony | An upgrade system that uses the Jewel of Harmony, refined from Gemstone. Gemstone drops in Kanturu, at 0.5% from monsters level 93 or higher. | Sockets and Harmony |
| IT | Illusion Temple, a team contest with six levels. The maps exist, but the event does not run today. | Illusion Temple |
| Jewel | A consumable that improves gear: Bless, Soul, Life, Creation, Guardian, Chaos and Harmony. It drops at 0.1% and only from monsters level 76 or higher. Here jewels stack, up to thirty per slot. | Jewels |
| Luck | An option that raises your critical chance and, above all, adds 25 percentage points to the refining chance in the Chaos Machine. An item with luck is far more valuable than it looks. | Item options |
| Mastery | The top end gear line imported from Season 20: ten armor tiers and 130 weapons and shields, from Bloodangel to Lightning. | Mastery sets |
| Mix | Combining items in the Chaos Machine. Talking about a wing mix or a +13 mix means the matching recipe. | Chaos Machine |
| ML / master level | The level that starts after 400. Each master level gives one point of skill tree. It only pays when killing monsters level 95 or higher. | Master level |
| Option / additional option | The extra bonus an item can have, shown as an additional value in the tooltip. On this server the drop ceiling is the equivalent of +16. | Item options |
| Orb | An item that teaches a skill when used. It comes in two families in the game: orbs and scrolls. Some are bought from the Skill Master, the NPC standing in the four cities. | Skill Master |
| PK | Player Killer. Anyone who kills other players outside a safe zone builds up murderer status and takes penalties for it. | PvP and PK |
| SD | Shield, the yellow bar under your health. It absorbs 90% of every hit before your health is touched. It always regenerates, and twice as fast in a safe zone. | HP, MP, SD and AG |
| Socket | Slots on an item, filled with spheres. They count toward the gear score, but they do not change the rarity of the piece. | Sockets and Harmony |
| Spot | A hunting point. Here it is not just slang: the classic maps have spots marked on the minimap, and clicking the marker sends your character there on its own. | Farming spots |
| Tier | A step in a gear line. On the mastery armor and weapons there are ten of them, from Bloodangel to Lightning, and the tier alone already sets a rarity floor. | Mastery sets |
| Total level | Normal level plus master level. The normal level caps at 400 and master goes to 1100, so the total reaches 1500. Every requirement above 400 in the game looks at this number. | Total level |
| Wing | Back gear. It gives defense, damage and damage absorption, and it is a requirement for some maps. It runs from the first to the fifth generation, and wing options count toward rarity just like excellent ones. | Wings |