Angel Room



Angel Rooms feature an angel and several free items: the divine equivalent of the Devil Room. Every time the Devil Room is spawned/entered, there's a chance for it to be replaced by the Angel Room if certain conditions are met. After beating the or  once, an Angel can be awoken by planting a bomb near the statue (or destroying it with  or similar items). This will begin an angel boss fight and allow Isaac to pick up or. Both pieces are needed to get through the Golden Door in The Chest or the Dark Room to fight Mega Satan.

Variations
The following room maps were made using Basement Renovator for cleaner viewing. Note that, unlike Devil rooms, items in Angel rooms cost nothing to take, but if there are multiple items, taking one will cause the others to disappear.

Normal
Items generated in these rooms pull from the Angel room item pool.

Greed Mode
Items generated in these rooms pull from the Greed Mode Angel room item pool.

If an Angel Room appears upon defeating Mom's Heart or It Lives, it will only contain a beam of light leading to The Cathedral.

Conditions to Make Angel Rooms Appear
For the player to have a chance to get an Angel Room after killing a boss (or with a card / Red Chest teleport), some conditions must be met:
 * A Devil Room door has spawned on any previous floor.
 * Teleporting to a Devil Room with a card or a Red Chest doesn't count.
 * No Deals with the Devil have been made throughout the run.
 * Taking red chest items, using, using , or collecting an item from Krampus doesn't count.
 * Even though it technically doesn't cost any health, taking a devil deal with will still prevent Angel Rooms from appearing.
 * and allow for Angel Rooms to spawn even if a Devil Deal was taken previously, as well as allowing to take Devil Deals without being locked out of Angel Rooms.
 * The "You feel blessed!" fortune from Confessionals allow for Angel Rooms to spawn even if a Devil Deal was taken previously, but only for the current floor.

Sacrifice Room Exception

 * On the 3rd and 5th sacrifice in a Sacrifice Room, there is a 66% chance that the player will receive the "You feel blessed!" effect. This will increase the chances of the Angel Room spawning even if the previous conditions have not been met.
 * On the 6th sacrifice in a Sacrifice Room, there is a 33% chance that the player will be teleported to the Angel Room if they haven't already visited or opened the Devil Room for that floor. This will occur even if the previous conditions have not been met.

Angel Room Generation Chance
The selection between Angel Room and Devil Room is made upon opening the door after defeating the floor's boss (or upon teleporting to the room using a card or a Red Chest).

The game makes a series of coin flips to determine if an Angel Room will appear or not. If one of these coin flips succeeds, an Angel Room is generated (except for the Devil beggar coin flip). If all the coin flips fail or no coin flips are done, a Devil Room is generated. Satisfying certain conditions gives additional coin flips with varying probabilities:

** These conditions share the same "coin flip chance" in Rebirth.

Examples
If Isaac meets the prerequisites and has with him, the game will make two coin flips to determine if he gets an Angel Room or not. The first coin flip has a 50% success chance and the second one has a 25% success chance. Isaac will only get a Devil Room if both coin flips fail, and he will get an Angel Room if one of the coin flips succeeds. The chance of failure is 0.5 * 0.75 = 0.375, which means the chance of success is 1 - 0.375 = 0.625. Thus, Isaac has a 62.5% chance to get an Angel Room -- take note that the result is not simply the sum of the coin flip probabilities 50% + 25% for 75%.

If Isaac meets the prerequisites, has, and has destroyed a Devil Beggar on the current floor, the chance to fail all coin flips (and get a Devil Room) become 0.5 * 0.75 * 0.75 = 0.28125, which means that the chance of success is 1 - 0.28125 = 0.71875. Thus, Isaac has a 71.875% chance to get an Angel Room.