MARATHON VAULT BREAKER
Dates, Vault Data, and how the mode works.
Marathon's first experimental PvE mode: a roguelite run through progressively tougher Vaults inside Cryo Archive, played Solo, Duo, or Trio at any Runner Level. Runs July 21 to August 4, 2026 with Update 1.1.5.
At a Glance
Vault Data
Vault Data is the mode’s currency and the main thing you carry out. It comes in two tiers, and they are earned differently.
- Solving Vaults — you must exfil to keep it.
- Killing a UESC Commander — credited after the run whether or not you exfil.
Solving consecutive Vaults in a single run, then exfilling. That is the only way to earn it.
The UESC Commander is the source most coverage misses. Because it pays out even on a failed run, it is the one way to leave a bad run with something.
What Leaves With You
Items and gear you find during a run do not exfil with you. The only things that leave the mode are event currency and designated event rewards.
The Sponsored Kit
You do not bring your own loadout. Vault Breaker gives you a free Sponsored Kit from the Vault Breaker Armory tab in the Events section, and you build it up with Vault Data.
- Weapon quality
- Survivability
- Implants and cores
Kit upgrades persist across runs. Cradle and Faction upgrades are enabled inside the mode.
The Vault Breaker Armory
- Tier 1 items: 3× or 5× per week, depending on the item.
- Tier 2 items: 1× per week — or convert to Tier 1 and buy 5× per week.
- Prestige Weapons: one of each, per event.
Armory purchases do not change your loadout inside Vault Breaker. Bungie’s note: purchases from the Weekly and Limited Offers “apply only to standard Marathon activities. Only Kit Upgrades will alter your loadout in Vault Breaker.” Buy gear to take out of the mode; spend on Kit Upgrades to get stronger inside it.
The Compiler
Vault Breaker went live on July 21, 2026. At the time of writing, nobody has fought the Vault Breaker version of the Compiler, us included. Bungie named it and described nothing. This section separates what Bungie has stated, what the Compiler does in the base Cryo Archive fight, and what Vault Breaker's ruleset implies but nobody has verified. We will update it once we have fought it ourselves.
The Compiler appears in Vault Breaker. Bungie's Vault Breaker Overview (2026-07-20) lists it as the culminating threat, after UESC hordes and vault security measures. That is the entire statement. No mechanics, no arena, no rewards.
The Compiler is not new. It is the existing endgame encounter at Cryo Archive's Vault 7, and Vault Breaker reuses it. In Cryo Archive, the fight works like this:
- In Cryo Archive: three terminals must be activated with matching symbols, which spawns a green shield bubble at the centre of the arena.
- In Cryo Archive: damage phases happen inside the bubble, where the shield core is exposed and shootable.
- In Cryo Archive: its attacks include lasers and tracking orbs.
- In Cryo Archive: the arena is reached by completing the run to the final vault.
This comes from playing the base-game encounter, not from Bungie. Bungie has published no description of the Compiler fight, and no article on this site that mentions the Compiler cites bungie.net. Our own Cryo Archive endgame guide describes the same encounter, but that is our coverage rather than a source, so it is offered as further reading and not as corroboration. Whether Vault Breaker changes any of this is unknown.
Vault Breaker's ruleset implies the following. None of it has been verified in game, none of it comes from Bungie, and any of it may turn out to be wrong.
- Expected: no rival Runners, so no third-partying and no contested exfil. This follows from the mode being pure PvE, not from anything Bungie said about the Compiler.
- Expected: Sponsored Kit progression should make later attempts easier, since kit upgrades persist across runs.
- Expected: in-run gear does not exfil, so a Compiler kill should pay out in Vault Data and Codex cosmetics rather than gear.
Not yet verified in game.
Codex & What Comes Next
Four Codex challenges run with the event, each rewarding a cosmetic:
- Profile Emblem — Opposition marker
- Profile Background — UESC Command
- Circuit Breaker Weapon Style — UESC Bulwark
- Weapon Charm — USEC Control
“USEC Control” is spelled that way in Bungie’s announcement, where every other entry reads UESC. Reproduced as written rather than silently corrected.
Bungie frames Vault Breaker as a test ahead of a full PvE offering in Season 3, which arrives September 22, 2026.
FAQ
When does Marathon Vault Breaker start?
Vault Breaker runs from July 21 to August 4, 2026. It arrives with Update 1.1.5 and is a limited-time event.
How do you get Vault Data in Vault Breaker?
Tier 1 Vault Data comes from two sources: solving Vaults (you must exfil to keep it) and killing a UESC Commander (credited after the run whether or not you exfil). Tier 2 Vault Data comes only from solving consecutive Vaults in a single run and then exfilling.
Does gear carry out of Vault Breaker?
No. Items and gear found during a run do not exfil with you. Only event currency and designated event rewards leave the mode.
Is there a Runner Level requirement for Vault Breaker?
No. Vault Breaker is open at any Runner Level, and can be played Solo, Duo, or Trio, either matchmade or as a premade group.
Is the Compiler in Marathon Vault Breaker?
Yes. The Vault Breaker Overview from Bungie names the Compiler as the culminating threat, after UESC hordes and vault security measures. The Compiler is the existing endgame boss at Vault 7 in Cryo Archive, which Vault Breaker reuses. Bungie has not described how the fight differs inside Vault Breaker.
Sourced from Bungie’s Marathon Mid-Season 2 Update Preview (2026-07-16), Vault Breaker Overview (2026-07-20), and Marathon Dev Team Update: Key Dates (2026-06-23). Checked against all three sources on 2026-07-21 — not yet verified in game. Vault Breaker is a limited-time event; details may differ from the announcements now that the mode is live.