MU Online Season 21 — All Updates & Patch Notes
MU Online Season 21 is the game's most expansive update yet, introducing the brand-new Crusader class, two fresh hunting zones — Aquila's Temple and Forgotten Raklion — plus sweeping balance changes, new Legendary equipment tiers, and the 9th Mastery Earrings. Released in multiple parts through 2025–2026, Season 21 raises the level cap, overhauls the Deep Dungeon, and refines character stat formulas across all classes. This page collects every official patch note for Season 21, organised by release part, so you can track every change from Part 1-1 through Part 2-2.
What’s New in Season 21?
What is the Crusader class in Season 21?
The Crusader is MU Online's 16th playable character class, introduced in Season 21 Part 1-1. It is a heavily armoured melee fighter with unique skill combos, exclusive equipment sets added in Part 1-2, and a distinct playstyle focused on sustained close-range combat and high defence. Like other advanced classes, the Crusader has a dedicated skill enhancement tree and 4th-class evolution path.
What new maps were added in Season 21?
Season 21 added two new maps: Aquila's Temple, introduced as an exploration zone in Part 1-2 and expanded with an Elite Hunting Zone in Part 1-3; and Forgotten Raklion, a brand-new hunting map released in Part 2-2 aimed at high-level players pushing the expanded level cap.
What are the 9th Mastery Earrings?
The 9th Mastery Earrings are a new tier of accessory equipment added in Season 21 Part 2-2, continuing the Mastery Earring progression system introduced in earlier seasons. Each tier provides increasingly powerful stat bonuses. The 9th tier represents the current endgame earring tier, requiring high-level crafting materials and offering significant offensive and defensive boosts across all character classes.