How to find Devil Rooms (And Angel Rooms) [Afterbith/Rebirth]

Overview

Looking to find a way to exchange your soul for upgrades? Or perhaps for those angels and their gifts? Look no further!

Introduction

I wrote this guide in order to help people find these Devil rooms more easily so you can give me your life, and I hope you will be somewhat enlightened before you finish! I will also cover Angel rooms, which can be much more annoying.

Updated with Afterbirth 7/02/16.

Devil Rooms

Red hearts are very important! If you lose them, your prospective buyer may rethink his choice. Losing red hearts in a boss fight ESPECIALLY lowers your chance to find a Devil Room. This being said, it might be best for you to leave those sacrifice rooms until after the devil rooms, unless you have soul/evil hearts, because they don’t count!

Don’t leave the Boss Room after one spawns! The chance for it spawning when you re-enter are halved, and so on and so forth.

Killing a beggar increases your chances to enter a Devil Room. It doesn’t matter if it is a Normal, Devil, Key, or Skull. However, in Afterbirth, Skull and Key no longer count. Holding the Book of Revelations while you slay the boss also helps, however, having the Book of Belial during a boss fight GURANTEES it. The Pentagram and the Black Candle also increase the chance, with Pentagram stacking, and the Goat Head is an upgrade solely there for spawning the Devil Room.

If you can’t keep your Red hearts during the floor without other upgrades, don’t worry! If you take no Red heart damage during the Boss fight, there’s still a chance for a Devil Room.

The Devil Room has a higher chance to spawn if the second last floor you were in had a Devil Room, with a slightly lower buff coming off if it was just in the previous floor. Seeing a Devil Room 3 or more floors ago has no effect on your chances.

In Afterbith, a lot of the items were nerfed. Black Candle, Pentagram, and Book of Revelations chances’ given were basically cut in half, but the Book of Belial took the worst hit, going from 2500% to 12.5% chance if used.

Just something I thought I might mention: Forcefully closing the game has a chance to break the Devil Room. Examples of this include offering the Sad Onion and the typical Breakfast, and Red Chests within ALWAYS containing an item.

Angel Rooms

If these conditions are met, the chances of an Angel Room/Devil Room spawning are 60%/40%:

• A Devil Room spawned on the previous floor. Teleporting to it beforehand via red chests or the Joker doesn’t count, but you don’t have to actually enter it.
• You have not done ANY deals with the devil. This doesn’t include picking up the black hearts, opening a red chest (Picking up an item within also doesn’t count), using the credit card or picking up Krampus’ loot/item, but doing anything else gurantees no Angel Rooms for the rest of the run.

Having the Rosary Bead increases the chances to 75%/25%, but the Bible Tract doesn’t affect any of this. (It only increases Eternal Heart drop chance)

Obtaining the “You Feel Blessed!” reward in the sacrifice room increases the chance quite a bit. The funny thing is that there are two “You Feel Blessed!” rewards obtainable from the Sacrifice Room, and obtaining both increases your chances by over 50%.

NB: Dealing with the Devil Beggar until he gives an item of the current floor does a quick coin flip determining what kind of room you get, with Devil Room at 90% and Angel Room at 10%. This decision overrides all other probability checks done by the game.

Spoiler tips:
Having Key Piece 1 or 2 increases your chance of finding an Angel Room, which can be combined with Rosary Bead nicely.

Conclusion

Thanks for reading this, and I hope this guide will be helpful with your runs of the Binding of Isaac: Rebirth. Feel free to point out any errors!

Good luck, and have fun!