That means that, with Chaos, approximately one out of every nine items you uncover will come from the Devil Room pool. So, how many items are in the relevant item pools? According to the Wiki, there are 50 items in the Devil Room pool and 436 items in general. * Here’s the big one: *You’re playing the devil room strat - that is, you want to maximize the number of devil-room items you get over the course of the game.*** This is admittedly a simplistic model, but since many players (myself included) use this as a general strategy I feel it’s a worthwhile strategy to model Chaos usage after.įrom the Wiki: “Causes items to be chosen from random Item Pools.” (We’re going to ignore the pickups it drops for the purposes of this guide, since unless you’re getting a Curved Horn/Cancer or a bomb which uncovers a Small Rock they probably won’t swing your game in the same way the item’s main effect does.)

I don’t know if this is true or not, but it will simplify things. * All items are equally weighted with Chaos. This is not always something that will happen - Krampus or no items on Floor 2 are all too common - but it will simplify things for the time being. * You don’t run into an angel room on the run. (This is also not always a fair assumption to make, but - again - it makes this guide easier.) * From floor 2 to floor 8, you don’t take any red heart damage until the boss is defeated. (This is admittedly not an assumption that will apply to most people, but for the purposes of making the math easier we’ll make it anyway.)

* You’ve unlocked every item in the game. This means that you’ll be getting 1-2 items per shop. I’ve seen a lot of discussion as to whether Chaos is a good item, and - with the help of some people who have done a lot of great work in determining the probabilities of a few occurrences in Isaac - this guide should help make a few Chaos decisions clearer.īefore we start, here are a few assumptions I’ll be making: Hi there! This is a general guide for when you should take Chaos in the Binding of Isaac: Afterbirth.

The binding of isaac chaos