How to Unlock The Lost in The Binding of Isaac: A Comprehensive Guide

The Lost, one of the most notoriously difficult and rewarding characters in *The Binding of Isaac*, is known for his spectral form, flight, and a significant lack of health. Unlocking The Lost is a rite of passage for many *Isaac* players, a testament to perseverance and mastery of the game’s mechanics. While the unlocking method has changed over different iterations of the game, this guide will focus on the current, Afterbirth+ (and Repentance) method, providing a comprehensive, step-by-step walkthrough to finally add this challenging character to your roster.

Understanding the Challenge: Why Unlock The Lost?

Before diving into the nitty-gritty, it’s important to understand *why* players subject themselves to this unlock. The Lost starts with the following:

* **Spectral Form:** He can fly and is immune to obstacle-based damage (spikes, rocks, etc.).
* **No Health:** He starts with zero health and no Soul Hearts. One hit means death.
* **Holy Mantle (Afterbirth+ and Repentance):** In Afterbirth+ and Repentance, The Lost starts with the Holy Mantle item, which allows him to take one hit without dying. This is a crucial advantage compared to the original unlocking method.
* **Eternal D6 (Repentance):** In Repentance, The Lost starts with the Eternal D6 instead of the regular D6. This item re-rolls items in the room, but unlike the D6, the Eternal D6 can re-roll items into weaker items or even completely remove them. It adds another layer of difficulty and strategic depth.

Despite the extreme challenge, playing as The Lost can be incredibly rewarding. His ability to fly opens up new paths and secrets, and the Holy Mantle provides a crucial safety net. Successful runs with The Lost often require creative thinking, skillful dodging, and a healthy dose of luck.

The Current (Afterbirth+ and Repentance) Unlock Method: The Four Deaths

The current method for unlocking The Lost in *The Binding of Isaac: Afterbirth+* and *Repentance* requires you to die in specific ways on specific floors while playing as specific characters. This must be done in the correct order. The sequence of deaths is as follows:

1. **Die to a Mulliboom as Isaac in the Basement or Cellar:** This means any variation of Mulliboom (the exploding mushroom enemy) must be the killing blow on the Basement or Cellar floor. Playing on Normal or Hard doesn’t matter.
2. **Die to your own Bomb as Magdalene in the Caves or Catacombs:** You must die from the explosion of your own bomb while playing as Magdalene. Again, Normal or Hard difficulty doesn’t matter. It has to be your own bomb, not a bomb dropped by an enemy or triggered by an item.
3. **Die to Mom’s Foot as Judas in Depths or Necropolis:** This one is more specific. You *must* die to Mom’s foot stomp attack (the attack where her foot slams down) in the Depths or Necropolis. Other attacks from Mom’s Heart or It Lives! do not count. Normal or Hard does not matter.
4. **Die to Azazel by dying to any non-self-inflicted damage in Womb/Utero II or Scarred Womb II:** This is perhaps the most difficult and misunderstood step. You need to die as Azazel on Womb II or Utero II or Scarred Womb II to *any* damage source *except* yourself. This means any enemy attack, hazard, or environmental damage must be the killing blow. This includes Mom’s Heart attacks if on Womb II and It Lives! attacks if on Scarred Womb II.

Detailed Walkthrough: Step-by-Step Instructions

Let’s break down each step with detailed instructions and helpful tips to ensure you unlock The Lost without pulling your hair out.

Step 1: Isaac and the Mulliboom

* **Character:** Isaac
* **Floor:** Basement or Cellar (Floor 1 or Floor 1 Alt)
* **Enemy:** Mulliboom (any variation)
* **Difficulty:** Doesn’t matter

**Strategy:**

1. **Play as Isaac:** Begin a new run as Isaac.
2. **Find a Mulliboom:** Explore the Basement or Cellar until you encounter a Mulliboom. Mullibooms are usually found near mushrooms and appear as small, round mushrooms with a fuse on top.
3. **Lower Your Health:** If you start with full health, intentionally take damage from other enemies or environmental hazards to lower your health to one or two hearts.
4. **Positioning is Key:** Once you find a Mulliboom, position yourself close enough to it so that its explosion will kill you, but far enough away that you don’t accidentally kill it first. Mullibooms explode when they are damaged or when you get too close.
5. **The Sacrifice:** Allow the Mulliboom to explode and kill you. Make sure the Mulliboom’s explosion is the final blow.
6. **Confirmation:** If done correctly, you will see Isaac’s death animation. Move on to the next step.

**Troubleshooting:**

* **Not finding a Mulliboom:** If you are having trouble finding a Mulliboom on the first floor, consider restarting the run. It can save you time in the long run.
* **Accidentally killing the Mulliboom:** Be careful not to kill the Mulliboom before it explodes. Use minimal damage attacks if necessary, or try to bait it into exploding near you.
* **Dying to another enemy:** Make sure the Mulliboom is the one dealing the final blow. Clear out any other enemies in the room before attempting this step.

Step 2: Magdalene and the Bomb

* **Character:** Magdalene
* **Floor:** Caves or Catacombs (Floor 2 or Floor 2 Alt)
* **Cause of Death:** Your own bomb
* **Difficulty:** Doesn’t matter

**Strategy:**

1. **Play as Magdalene:** Begin a new run as Magdalene.
2. **Find Bombs:** Magdalene starts with the Yum Heart item, which can heal you. However, for this step, you’ll need bombs. If you don’t have any to start with due to items, look for bomb pickups in rooms or buy them from shops.
3. **Lower Your Health:** Reduce your health to one heart or half a heart. If you have full health plus extra hearts, you may need to take a few hits from enemies or environmental hazards.
4. **Plant the Bomb:** Place a bomb near yourself and wait for it to explode. Ensure you are within the blast radius.
5. **The Suicide Bomb:** Let the bomb explode and kill you. It *must* be your own bomb; bombs dropped by enemies or triggered by items will not count.
6. **Confirmation:** Witness Magdalene’s demise. Time to move on.

**Troubleshooting:**

* **Not finding bombs:** Prioritize finding bomb pickups or purchasing them from shops. Explore every room thoroughly.
* **Dying to an enemy while placing the bomb:** Clear out any enemies in the room before attempting to place the bomb.
* **Accidental Heal:** Be careful of Magdalene’s Yum Heart. Avoid using it if you have low health and are trying to die to a bomb.
* **Incorrect floor:** Make absolutely sure you are on the Caves or Catacombs floor (floor 2 or floor 2 alt). Dying with a bomb on the wrong floor will ruin the run.

Step 3: Judas and Mom’s Foot

* **Character:** Judas
* **Floor:** Depths or Necropolis (Floor 3 or Floor 3 Alt)
* **Enemy/Attack:** Mom’s Foot Stomp
* **Difficulty:** Doesn’t matter

**Strategy:**

1. **Play as Judas:** Begin a new run as Judas. Remember Judas starts with only one heart, so you will need to be very careful.
2. **Reach Depths or Necropolis:** Play through the Basement/Cellar and Caves/Catacombs floors and defeat the bosses to reach the Depths or Necropolis.
3. **Mom Fight:** Enter the boss room to initiate the Mom fight.
4. **Dodge and Weave:** Focus on dodging Mom’s attacks. The key is to survive long enough to be killed by her foot stomp attack. Mom has multiple attacks, but only her foot stomp attack counts for unlocking The Lost.
5. **The Stomp:** Position yourself so that Mom’s foot will stomp on you. This may require some careful maneuvering.
6. **The Crushing Blow:** Allow Mom’s foot to crush you, dealing the final blow.
7. **Confirmation:** You will see Judas die, crushed by Mom’s foot. Onward!

**Troubleshooting:**

* **Dying to other Mom attacks:** This is the most common mistake. You *must* die to the foot stomp attack. The other attacks, such as the knife attacks or the dropping enemies, will not count.
* **Reaching Mom with too much health:** Judas only has one heart, but if you manage to obtain extra hearts, make sure to take damage to reduce your health to one heart before the foot stomp.
* **Having trouble dodging:** Focus on learning Mom’s attack patterns. Her foot stomp attack is telegraphed, giving you a brief window to move out of the way. If you find items that increase speed and/or damage, prioritize damage to quickly kill mom and start a new run, since you need a specific attack to kill you.

Step 4: Azazel and the Womb/Utero/Scarred Womb

* **Character:** Azazel
* **Floor:** Womb II or Utero II or Scarred Womb II (Floor 5 or Floor 5 Alt)
* **Cause of Death:** Any non-self-inflicted damage
* **Difficulty:** Doesn’t matter

**Strategy:**

1. **Play as Azazel:** Start a new run as Azazel. Azazel’s powerful starting ability makes reaching the Womb easier.
2. **Reach Womb II/Utero II/Scarred Womb II:** Successfully navigate through the previous floors to reach Womb II, Utero II, or Scarred Womb II.
3. **Avoid Self-Inflicted Damage:** This is *crucial*. Do not die from your own bombs, self-inflicted damage from items, or by using the Razor item. Any other damage source is acceptable.
4. **Deliberate Sacrifice:** Find an enemy or hazard and allow it to kill you. Do not use your Brimstone attack, your starting bomb or any other way to inflict damage to yourself. Let an enemy kill you.
5. **Confirmation:** You will see Azazel die from a non-self-inflicted source on Womb II/Utero II/Scarred Womb II. The Lost should now be unlocked.

**Troubleshooting:**

* **Accidentally killing yourself:** This is the most common mistake. Be extremely careful not to use bombs, damage yourself with items, or use any other self-inflicted damage source. The damage needs to come from an outside source.
* **Dying on the wrong floor:** Double-check that you are on Womb II or Utero II or Scarred Womb II before attempting this step.
* **Getting overpowered:** Azazel’s Brimstone can easily carry you through the early floors. However, avoid becoming *too* powerful, as you need to die in a specific way on the Womb. Be careful when picking up items that may deal contact damage or give you bombs, and make sure to not use any of them.

Important Considerations and Tips for Unlocking The Lost

* **Do it in a single session:** While not definitively confirmed, many players report higher success rates when completing all four deaths in a single game session without closing the game.
* **Seed Runs:** This unlock *cannot* be achieved using seed runs. The game specifically prevents The Lost from being unlocked if you are using a seed.
* **Confirmation Pop-Up:** You should see a pop-up confirming that you have unlocked The Lost after the fourth death. If you don’t see this, something went wrong, and you’ll need to start over.
* **Use a notepad:** Track your progress to ensure you don’t lose track of which death you’ve completed.
* **Practice Dodging:** The Lost’s fragility makes dodging a crucial skill. Practice dodging enemy attacks to improve your survivability.
* **Be Patient:** Unlocking The Lost can be frustrating, but don’t give up! With persistence and careful planning, you’ll eventually succeed.
* **After unlocking, enjoy:** Remember to enjoy playing as The Lost once you’ve unlocked him! He’s a challenging but rewarding character to play.

What to do after unlocking the Lost?

Congratulations, you have unlocked the Lost! What now? Here’s how to handle this character and how he changed through the versions of Isaac:

* **The base Game’s Lost** was pure pain. No Holy Mantle. No extra lives. Just pure skill, dodging and tears, and luck. It was regarded as the hardest character in the entire game.
* **Afterbirth’s Lost** was still hard, but he was granted the Holy Mantle as a starting item, granting him one free hit per room, but still retaining the no health gameplay.
* **Afterbirth+’s Lost** gained the ability to hold any amount of Holy Cards, and would respawn with the held card upon death. This made the Lost a lot better, due to the fact he can respawn.
* **Repentance’s Lost** changed the character a lot. The ability to hold any amount of Holy Cards was removed, making respawning harder, the Holy Mantle was retained, and instead of starting with the D6, he would start with the Eternal D6. This item rerolls items in the room, but is not as good as the normal D6, since it can remove items, or even turn them into worse ones. This made the lost even harder than Afterbirth+’s Lost, and is widely regarded as one of the hardest characters in the game, second only to Tainted Lost.

To get the completion marks on the Lost, try to play as normally as possible. The lost has one free hit per room, and then is one hit away from dying, so remember to use Sacrifice Rooms if you are running out of health and need to find a way to get health (since the sacrifice room can also give angel items). Keep rerolling the items you find until you get something that is broken and can carry you. This is the most important part. The lost can reroll any item into any other item, meaning you can abuse this feature to get a run winning item. Also, if you start with a bad item that is harming the run, reroll it with the Eternal D6.

Unlocking The Lost is a significant achievement in *The Binding of Isaac*. It requires patience, skill, and a little bit of luck. By following this comprehensive guide, you’ll be well on your way to conquering this challenging unlock and experiencing the unique gameplay that The Lost offers. Good luck, and happy dying… for a good cause!