Horrors of Kairos is live for a limited time. The event window is October 23 through November 6, and the rollout follows a single global schedule.

Start End Platforms Time zone guide
Oct 23, 2025, 10:00 AM PT Nov 6, 2025, 10:00 AM PT All platforms 10 AM PT · 1 PM ET · 17:00 UTC

Once the window opens, any world boss encounter takes place under the event rules detailed below.

What’s new during Horrors of Kairos

  • Seasonal weather: all world boss fights occur under a blood-rain variant.
  • New world-boss drops:
    • Murmur (Legendary Tediore Assault Rifle): executes weakened enemies with guaranteed critical hits on targets under 35% health.
    • Skully (Legendary Order Grenade): a homing grenade that seeks the nearest target and fires projectiles.

World boss kill rewards are delivered automatically to the Reward Center in your Inventory, under Equipment.

Free cosmetics via SHiFT code

A limited-time SHiFT code unlocks two cosmetics for all players:

  • Gourd Your Loins Vault Hunter head (pumpkin) for Vex, Rafa, Amon, and Harlowe
  • Hex Appeal universal weapon skin
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Redeem the code using your SHiFT account; detailed instructions are in the official SHiFT User Guide.

How and where the loot drops work

  • Defeat any world boss during the event window to roll for Murmur and Skully.
  • Event drops are not picked up in the arena: check the Reward Center in your Inventory (Equipment tab) after the kill.
  • The seasonal blood-rain effect appears only in world boss encounters; regular activities play as normal.

Availability, requirements, and fine print

  • Horrors of Kairos is free for all Borderlands 4 players.
  • The SHiFT code requires a SHiFT account and an internet connection.
  • Cosmetic code redemption is limited to one per SHiFT account and must be redeemed by December 31, 2030.
  • The event ends on November 6 at 10:00 AM PT.

If you’re jumping in for the legendaries, target world bosses during the window and check your Reward Center between runs. If you want the cosmetics, redeem the SHiFT code once, then equip the pumpkin head and weapon skin from your customization menus.