How to Unlock The Lost in The Binding of Isaac: Rebirth

Last Updated: November 2, 2020

The Lost is the ultimate challenge in The Binding of Isaac: Rebirth. He has bad stats and can never have health, which means he will always die in one hit. But The Lost also unlocks some of the best and most fun items in the game and is needed to get the final achievement, True Platinum God. Unlocking him is pretty simple if you use seeded runs, which should only take about 40 minutes.

Note: You must do these in order without dying to anything else in between.

Method 1

Method 1 of 2:

Rebirth

1
Die to a Mulliboom in the Basement or Cellar as Isaac.
- On the character select screen before starting a new run, press tab, type in this seed: JTMD EZPF, then select Isaac.
- Go left after you start and let the enemies damage you until you have only a half heart of health left.
- Go to the room below your starting room and die to the Mulliboom.
2
Die to your own bombs in The Caves or Catacombs as Magdalene.
- Input this seed: 349W VRFT.
- Go to the item room right above you and pick up Pyro, which will give you 99 bombs. These bombs should be enough to help you kill the bosses and enemies of the next two floors.
- Once you reach The Caves or its alternate floor, The Catacombs, drop bombs next to yourself until you die.
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3
Die to Mom as Judas.
- Input this seed: YR8E YXDV.
- The first item room will give you Polyphemus, and if you skip the devil deals that are guaranteed by The Book of Belial, you will get very strong items from Angel rooms.
- Once you've worked your way through to the Depths 2 and found the boss room, lower yourself to half a heart and walk in. Mom will always stomp as her first attack.
4
Die to the 2nd stage of the Satan boss fight as Azazel. This is the final step in unlocking The Lost, which means you cannot use a seed. Luckily Azazel is considered by many the easiest character.
- Reset your runs by holding R until you find a good first item, get rid of any black hearts, and avoid picking up items that do damage independently of you like Demon Baby or Daddy Long Legs.
- Once you reach the boss fight in Sheol, die to the 2nd stage of the fight where Satan is shooting lasers and tears out of his hands while moving around the room.
5
Finished! If you did everything right you'll have unlocked The Lost. Enjoy the many grueling hours it will take to get all his unlocks.

Method 2

Method 2 of 2:

Afterbirth

1
Unlock the missing poster. This is accomplished by beating the Lamb while playing as Isaac. Since the Lamb is in the Final Boss of the dark room, you will have to unlock it first. You need to unlock the Negative, which you get by beating Satan 5 times. After defeating Satan, you have to touch the golden chest he drops and then you will get to the Dark room.
2
Start a run with Isaac. Find the missing poster. A good way to do this is to go to the shop, and try and buy Mom's Box, as it can be used to spawn a random trinket, including the missing poster. Take this poster and go to a Sacrifice Room
3
Die in a Sacrifice Room. In Rebirth, doing this showed you one of the 4 people you have to die with and how to die with them to unlock the Lost, however in Afterbirth, you only have to do this with Isaac and the Lost will be unlocked.

Community Q&A

Question

Is it worth unlocking it if you're not going for Real Platinum God?

Community Answer

The items are definitely worth the effort and pain of doing everything as the lost, as they are really strong, helpful, and might as well be OP. It is harder to unlock the lost in Rebirth but in Afterbirth you got 3 more challenges on the completion post-it note. It can be a pain but, like I said, worth it.
Question

Does picking up the dead cat and dying on one of the early lives affect how the azalea part works in Binding of Isaac?

Community Answer

No, it doesn't. It needs the actual death screen to count for you to restart.
Question

Will The Lost unlock if I use seeds?

Community Answer

You can use a seed for the first three characters in Rebirth, but not for Azazel.