To understand the modern, layered endgame of POE 1 Boosting, one must look to its beginning. The very first challenge **league**, launched alongside the game's open beta in 2013, was **Onslaught**. Its premise was simple yet brutal: all monsters had 20% increased attack speed, cast speed, and movement speed. This set the template for all future leagues: a fresh economy, a new mechanical twist, and a distinct identity that would, if successful, leave a permanent mark on the game. **Onslaught**'s legacy is not a mechanic in the modern Atlas, but the philosophy it embodied.

**Onslaught** was a **league** of pure, unadulterated challenge. It offered no new NPCs, no complex systems to master—just faster, deadlier versions of every creature in Wraeclast. This focus on heightened difficulty tested the limits of early builds and player skill, establishing from the outset that *Path of Exile*'s temporary leagues were for those seeking a tougher, fresher experience. The mechanic was so well-received that it was later added to the core game as a mod that can roll on magic monsters and as a buff players can obtain, its name forever tied to that inaugural season of speed and peril.

The success of **Onslaught** proved the model. It showed that players were eager for regular resets and new rules. The following league, **Anarchy**, introduced rogue exiles—powerful player-like NPCs that could appear anywhere, adding unpredictable danger. Then **Domination** brought shrines with powerful temporary buffs. These early leagues were focused on modifying the core combat experience rather than adding parallel progression systems. They were the building blocks, demonstrating that even small twists could rejuvenate the entire game for three months.

The spirit of **Onslaught**—of creating a specific, pervasive environmental challenge—echoes in later hardcore variants like **Ruthless**, but its true heir is the philosophy of the challenge league itself. Every three months, the game asks: "What if the world worked this way now?" From **Onslaught**'s simple speed boost to the complex board game of **Sentinel** or the roguelike dungeons of **Sanctum**, the core promise remains: a new world to learn, a new economy to conquer, and a new test for your exile to overcome. That promise, first made in the fever-dream pace of **Onslaught**, is the beating heart of *Path of Exile*'s enduring appeal.