Cast forbiddenbox in the Secrets menu. 16 rooms, 1,665 kills, one Darkasso.
Room 1665 hides behind the only spell the wiki explicitly calls the "intended method" of unlock. Other Secret menu spells in Vampire Survivors bypass standard unlock requirements; forbiddenbox is different. The wiki specifies that the stage achievement literally tells players "Dare to cast the spell forbiddenbox," which makes the spell itself the canonical entry route, not a workaround.
Once inside, the stage breaks the standard Vampire Survivors loop. Per the wiki, all modifiers except Arcanas and Limit Break are disabled at the start. The player spawns in a small locked room with no enemies, no Arcana selection, and no path forward until 100 kills crack open the first corridor. Each subsequent room unlocks at fixed kill milestones until the final room opens at exactly 1,665 kills (not 1,500).
Build context. According to the wiki, the stage carries x1.9 player and enemy move speed, x1.5 gold, x1.15 projectile speed, and a 0 starting spawn count. Enemies do NOT despawn when the player kites them off-screen, which inverts the standard tactic of running circles around the map. Light sources appear in dense clusters (11-12 per corridor) and slowly respawn, which keeps the loot economy alive across the 30-minute timer.
This guide covers the forbiddenbox spell, the 16-room kill-milestone progression, the Darkasso relic reward, the modifier quirks that change standard builds, and the mistakes that stall players in the early rooms before the first 100-kill door unlocks.
Cast forbiddenbox in the Secrets menu from the main menu. The Secrets menu is the canonical unlock path per the achievement description.
Darkasso relic in the final room, unlocked at 1,665 cumulative kills (not 1,500).The unlock is a single spell. From the main menu, open the Secrets menu (the hidden option behind the standard menu chord) and type forbiddenbox. The wiki specifies this is the only way to unlock Room 1665 and the intended method, distinguishing it from spells like coopwhen that bypass standard unlock requirements for stages with conventional routes.
| Step | Action |
|---|---|
| 1. Open the Secrets menu | From the Main Menu, two methods exist to surface the hidden Secrets menu |
| 2. Cast the spell | Type forbiddenbox in the spell input field |
| 3. Room 1665 appears in Stage Selection | The stage is now permanently available with the ID DEVILROOM |
| 4. Pick a character and survival kit | The first 100 kills are the hardest because no Arcana selection fires until the first room unlocks |
Per the wiki, the achievement description for unlocking the stage reads "Dare to cast the spell forbiddenbox," which is the strongest in-game evidence that the spell route is canonical rather than a developer Easter egg. The related Forbidden Box item in the Forbidden Scrolls of Morbane lets the player cast the same spell during a run as an alternative trigger.
The stage layout is a chain of 16 rooms connected by corridors. According to the wiki, rooms unlock at fixed kill counts of 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, and finally 1665. The jump from 1,400 to 1,665 is a 265-kill gap, the largest single milestone in the stage and the reason runs that stall at 1,400 do not always know how many kills are left.
| Room | Kills required | Notes |
|---|---|---|
| Spawn room (Room 1) | 0 | Small locked room, no Arcana selection, no starting enemies |
| Rooms 2-14 | 100 to 1,400 (every 100) | One corridor and one new room per 100 cumulative kills |
| Room 15 | 1,400 | Second-to-last room. Stage darkness reaches its peak here |
| Room 16 (final) | 1,665 | Contains the Darkasso relic. Stage fully lights up when this room opens |
Per the wiki, ~11-12 light sources appear in each corridor and slowly respawn over time, which keeps pickup income alive through the long run. Boss enemies generally have less health than non-boss enemies in this stage, which is the opposite of most stages. Enemy variety changes based on which rooms have been unlocked and how much time has passed.
Skip the Spinach passive entirely. Per the wiki, all stat modifiers except Arcanas and Limit Break are disabled at the start of Room 1665. In actual play, this means stacking damage-boost passives is wasted XP. Build into Arcanas and Limit Break for any stat scaling, then take evolution-gate passives like Empty Tome or Duplicator for the weapon evolution payoffs that still function normally.
Room 1665 carries the most aggressive modifier override of any base game stage. The wiki lists +90% player and enemy move speed (x1.9 each), +15% projectile speed, +50% gold, an enemy minimum of 20, and a 50% destructible chance that scales to 80% with Luck. Critically, the stage disables every other modifier the player would normally bring in.
| Property | Value |
|---|---|
| Player move speed | x1.9 |
| Enemy move speed | x1.9 |
| Projectile speed | x1.15 |
| Gold multiplier | x1.5 |
| Enemy minimum | x20 (constant pressure) |
| Starting spawns | 0 (player spawns in empty locked room) |
| Destructible chance | 50% base, 80% with Luck |
| Max destructibles | 20 |
 Arcanas | Enabled (not selectable at spawn, unlocks after 100 kills) |
 Limit Break | Enabled, applies normally |
| All other modifiers | Disabled (Hyper, Hurry, Inverse, Endless all suppressed) |
According to the wiki, the no-despawn rule is the second-biggest mechanical change. Enemies that the player outruns or kites off-screen stay alive and follow indefinitely instead of disappearing. The standard "kite the screen" tactic that works in Mad Forest or Cappella Magna does not work here, which forces stationary or near-stationary builds.
The build pattern that works here is Arcana-first plus an evolution-chain weapon that runs at high kill volume. The wiki notes Arcanas are the only stat modifier preserved at stage start, so picking a damage-multiplier Arcana (like Slash or Out of Bounds) at the first Arcana chest accelerates the 1,665-kill grind dramatically. Limit Break stays enabled for late-stage damage scaling once the run gets into 800+ kills.
Iguana Gallo Valletto (Clock Lancet starter pairs with Arcana selection out of the gate)Any high-Amount weapon (Garlic, Shuriken, or Bone for the multi-hit kill rate)Slash (XVI) or Out of Bounds (XII) (damage-multiplier Arcanas for the kill-volume grind)Across multiple runs, the milestone clear pattern lands around minute 18 for the 1,400 mark and minute 24-26 for the final 1,665 mark, assuming the build hit a damage-multiplier Arcana at the first chest. Without it, the run can stretch past the 30:00 time limit and trigger the Reaper before the Darkasso unlocks.
Darkasso is the only relic the stage drops. Per the wiki, it sits in the final room behind the 1,665-kill door. The room itself fully re-lights the stage after the previous rooms have progressively darkened, which is a visual confirmation that the relic spawn is imminent. The wiki notes there is little point continuing the run after the relic pickup.
| Property | Value |
|---|---|
| Relic name | Darkasso |
| Location | Final room (Room 16), unlocked at 1,665 kills |
| Stage visual cue | Stage darkens progressively per room, then fully re-lights when Room 16 opens |
| Stage theme | Call of the Bloodmoon |
| Achievement | "Dare to cast the spell forbiddenbox" |
According to the wiki, the run effectively ends with the relic pickup. The 30-minute time limit gives a buffer for slower builds, and the Reaper still spawns at the timer cap if the run drags past 30:00 without a relic pickup. In real runs, the Darkasso payoff is the only reason to continue past the 1,400 milestone; everything past that is the final 265-kill push.
Pair the Room 1665 grind with passive items that survive the modifier override, plus the Forbidden Box spoke for the in-run spell route.
Game data and screenshots adapted from vampire.survivors.wiki, used under CC BY-NC-SA 3.0. Original content remains the property of the wiki contributors and Poncle.