The Lost

The Lost is a secret character.

The Lost starts with no health and cannot gain health by any means. Therefore, it will die from any damage taken.

The Lost also starts with (if unlocked).
 * The Lost starts with flight.
 * The Lost starts with flight, spectral tears, (if unlocked) and  (after donating 879 coins to the Greed Machine).
 * The Lost starts with flight, spectral tears,, and the effect of (after donating 879 coins to the Greed Machine) This form of Holy Mantle is inherent to the character rather than being a starting item, and as such will be present when switching to The Lost in the middle of the run through the use of , will not be present when switching away, and cannot be removed by any means.

The Lost can activate the button in Greed mode without taking damage, in exchange of one coin less of the next wave's reward. The Lost can take devil deals and Black Market items for free.
 * Devil deals and Black Market items are presented as choices. Taking one will despawn all other deals in the room.
 * Unlike other choices, devil deals cloned with will not be a choice. All copies can be taken.
 * The Lost can take every devil deal in the first room of the if the red chests are opened one by one.

Item Interactions

 * : Prevents items with the internal tag  from spawning. In practice, this automatically rerolls most items that aren't beneficial to The Lost, namely ones that only give health, flight, and/or spectral tears or activate upon taking damage.

Unlocking The Lost in Afterbirth
The Lost is unlocked by dying in a sacrifice room while holding Missing Poster.


 * Looking for in shops makes finding the poster easier.
 * , in conjunction with a large enough or infinite source of bombs (such as a Gold Bomb), have a small chance to drop trinkets, making it easier to find the poster.
 * This method got nerfed, since now have a cap on drops per floor.
 * It is technically possible to unlock The Lost while holding Mysterious Paper, although the probability is small since it only has a 1/4 chance to imitate the Missing Poster. and other resurrection items could be useful for extra attempts.
 * Since always drop Mysterious Paper and have a cheap craft for  and his, a new possible method has been found where you spam runs getting the Divorce Papers early and dying in the first Sacrifice Room you can find. Even with the small chance of getting the unlock with Mysterious Paper, the high number of runs in a short period of time can be worth it.
 * Even while holding Missing Poster, if Isaac happens to teleport while taking the last heart of damage, you will die without unlocking The Lost. This includes sacrificing on the spikes in the middle of the sacrifice room past 11 times.

Unlocking The Lost in Rebirth
The Lost is unlocked by dying consecutively with certain characters, with no other deaths. Deaths must be completed in the order shown here, and seeds can be used for the runs except for the last with Azazel:


 * 1) Isaac must die to a Mulliboom in or.
 * 2) Magdalene must die to her own bomb in or.
 * 3) Judas must die to any Mom attack in or . Being killed by any monster spawned by Mom will spoil the entire attempt at unlocking The Lost.
 * 4) Azazel must die to any Satan attack in . Being killed by The Fallen in the boss room or a Kamikaze Leech will spoil the entire attempt at unlocking The Lost. Being killed by using doesn't count as a Satan kill.

The Lost will be unlocked after dying to Satan's attack.

Notes on unlocking The Lost

 * Multiple lives (for example, obtained by ) must be depleted before the intended death, as deaths while having extra lives do not count as a game loss.
 * Having any mods installed that triggers the mod flag will make The Lost unobtainable. To fix this problem, all mods have to be removed.
 * The game cannot be won as any character required to unlock it when unlocking it.
 * Champion versions of monsters and bosses will count for the death criteria.
 * Runs can always be safely reset.
 * Mom's Foot's stomp counts as explosive damage, which makes a problematic choice when trying to complete Step 3.
 * Picking the wrong character while unlocking him doesn't mess up the unlocking process.
 * Quitting and Restarting the game in the middle of the unlocking process doesn't mess it up.
 * Picking up, , or should be avoided. These items will revive the current character as a different one and therefore prevent the current unlock-step from being fulfilled.
 * Exploit: If you die during a required run, but hit the "start" button just as you die and reset before it shows the "Today I died" paper, it will not count as a death that spoils the run, instead it counts as a restart.

File Manipulation
By changing a file parameter, an unsuccessful try can be undone:


 * 1) Backup the file  found in the   by making a copy of it in the same folder.
 * 2) Open the original file with Notepad and change the  parameter in it to  . This will disable Steam Cloud gamesaves synchronization.
 * 3) After an unsuccessful try, delete the original file and rename the backup copy with the name of the original file:
 * 4) Repeat steps 1 after each successful run until you unlock The Lost.
 * 5) When finished, open the original file and restore the  parameter in it to  . This will enable Steam Cloud gamesaves synchronization again.

Helpful Seeds For Rebirth
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Isaac
GPE3 2T1H (Must be on Normal difficulty. 2 Mullibooms south of starting point. Use the sacrifice room above to damage yourself first) JTMD EZPF (Must be on Normal difficulty. One mulliboom directly below the starting. Go left first to get weakened) GH9Y FSA8 (Hard difficulty, series of rooms containing mullibooms going down) Q2V4 YZET (Hard difficulty, Cellar needs to be unlocked, 2x2 room full of mullibooms (about 6/7) when going up) GQHN NMKN (Go left, 4+ Mullibooms) 6Z2L AZ6J (Go left, 4+ Mullibooms) VNSM AHHG (Go up, weaken yourself at the spikes, then go up and die from the Mulliboom) PXRT XH49 (Go up, weaken yourself with the Frowning Gapers, then go down and die to the Mulliboom)

Maggy
ALFA 0NTS (Recommended Normal difficulty. Pyro in the first Treasure Room, adjacent to spawn) FDRG 0CTE (Pyro in the first Treasure Room, adjacent to spawn) DXVW MQCF (Pyro in the first Treasure Room) YGDC T8SL (10 bombs in the first Treasure Room)

Judas
YR8E YXDV (Must be on Normal difficulty. Polyphemus in the first Treasure Room. Do not take devil deals, as Trinity Shield and Sacred Heart will be available in Angel Rooms. Keep the Book of Belial to ensure they show up. Also, from the pills from Mom's Coin Purse (1st boss, Duke of Flies), take the orange (Health Up) then the white one (Full Health), ignore the blue ones (Speed Down)). N0G3 VLD4 (Both modes) - Dr. Fetus on floor 1, and Ipecac on floor 2. DMTM NRD9 (Do not make a Devil Room deal in Basement II will spawn an Angel Room with Holy Grail in Caves I. Collecting everything grant huge tears. 180Y 7RDC (Lots of health early (Rosary in first Treasure room), good pickups (Mulligan is in second Treasure room, Dr. Fetus and Mr. Mega in the third and fourth). Skip the first Devil deal, as the Angel deals are Sacred Heart, Mitre, and Scapular. Remember to trigger scapular before entering the Mom fight if you take it, as the immediate foot stomp may leave you with the bonus soul heart.)

The Lost
HNA6 WEK7 (Dead Cat and Holy Mantle on first floor, helpful for practice runs) }}

Trivia

 * When The Lost's unlock requirements were discovered through the use of data mining, Edmund McMillen and Tyrone Rodriguez both expressed their disappointment, considering it impatient and "like swallowing a hundred dollar steak in one bite".
 * Right before the start of a run, some images appear to hint to unlocking The Lost, including the Missing Poster and The Lost itself.
 * Dying in a Sacrifice Room while holding the Missing Poster would yield a puzzle piece on Isaac's last will. These puzzle pieces, when put together, created the last wills of characters dying in the method used to unlock The Lost.
 * Before version 1.02, The Lost would die if a run was exited then continued.
 * When The Lost picks up an item, tarot card, or pill, you can see its arms that do not connect to its body.
 * Internally, The Lost has half a soul heart, which is hidden behind a permanent Curse of the Unknown-like effect. The singular soul heart is why The Lost can "pick up" soul hearts, black hearts, and eternal hearts. There are no ways to increase this health, though, as The Lost's health is constantly reset back to half a soul heart.
 * Devil deals appear as requiring three soul hearts each as The Lost technically only has half of an invisible soul heart. This is cosmetic only, as devil deals are still free.
 * The Lost can pick up soul hearts within the small timeframe of invincibility granted by after getting hit.
 * A loading screen (when Isaac dreams) depicts the "Voice of God" telling Isaac's Mom to kill her son as The Lost speaking to her from the attic.
 * The Lost's starting health is listed as "?" on the character selection screen.