```mermaid
graph TD
    %% ACT I: Awakening
    Start((Start Game)) --> M01[M01: First Descent<br><i>Unlock: Tinker, Barracks</i>]
    M01 --> M02[M02: The Signal<br><i>Unlock: Marketplace, Scavenger</i>]
    M02 --> M03[M03: The Foundation<br><i>Unlock: Research, Vanguard</i>]

    %% ACT II: Faction Agendas (Parallel)
    M03 --> Hub{The Hub<br><i>Unlock: Side Ops</i>}

    Hub --> ChainA[Arcane Dominion Arc<br><i>Crystal Spires</i>]
    Hub --> ChainB[Cogwork Concord Arc<br><i>Rusting Wastes</i>]
    Hub --> ChainC[Iron Legion Arc<br><i>Frontier/Void</i>]
    Hub --> ChainD[Golden Exchange Arc<br><i>Mixed</i>]
    Hub --> ChainE[Silent Sanctuary Arc<br><i>Fungal Caves</i>]

    %% Chain A
    ChainA --> M04[M04: Unstable Aether]
    M04 --> M05[M05: Rogue Mage]
    M05 --> M06[M06: Reality Tear<br><i>Unlock: Battle Mage</i>]

    %% Chain B
    ChainB --> M07[M07: Factory Reset]
    M07 --> M08[M08: The Construct<br><i>Boss Fight</i>]
    M08 --> M09[M09: Data Recovery<br><i>Unlock: Field Engineer</i>]

    %% Chain C
    ChainC --> M10[M10: Hold the Line]
    M10 --> M11[M11: Breach & Clear]
    M11 --> M12[M12: The Warlord<br><i>Unlock: Warlord</i>]

    %% Chain D
    ChainD --> M13[M13: Supply Run]
    M13 --> M14[M14: Hostile Takeover]
    M14 --> M15[M15: The Auction<br><i>Unlock: Platinum Pass</i>]

    %% Chain E
    ChainE --> M16[M16: Cleansing]
    M16 --> M17[M17: Lost Spirits]
    M17 --> M18[M18: Source of Rot<br><i>Unlock: Custodian Mastery</i>]

    %% ACT III: The Fracture
    M06 & M09 & M12 & M15 & M18 --> Fracture{Civil War Begins}

    Fracture --> M19[M19: Diplomatic Immunity]
    M19 --> M20[M20: Sabotage<br><i>Choice: Legion vs Concord</i>]
    M20 --> M21[M21: Resource War]
    M21 --> M22[M22: False Prophet]
    M22 --> M23[M23: Spirequake]
    M23 --> M24[M24: The Ultimatum<br><i>Invasion Event</i>]
    M24 --> M25[M25: Into the Dark<br><i>Unlock: Act IV</i>]

    %% ACT IV: The Descent (Linear Gauntlet)
    M25 --> M26[M26: Iron Shell]
    M26 --> M27[M27: Crystal Heart]
    M27 --> M28[M28: Rotting Soul]
    M28 --> M29[M29: The Void]
    M29 --> M30[M30: Gatekeeper<br><i>Boss: Void Brute Omega</i>]
    M30 --> M31[M31: Ascension]
    M31 --> M32[M32: The Origin<br><i>Final Boss</i>]
    M32 --> End((Game Complete<br><i>New Game+</i>))

    %% Styling
    classDef story fill:#f9f,stroke:#333,stroke-width:2px;
    classDef boss fill:#b00,stroke:#333,stroke-width:4px,color:#fff;
    classDef unlock fill:#0b0,stroke:#333,stroke-width:2px,color:#fff;

    class M01,M02,M03 story;
    class M08,M12,M18,M30,M32 boss;
    class M06,M09,M15 unlock;
```