I installed ProjectE, PEI, and a few other mods on top of v5.12.0 of the "All The Mods" modpack.

Upon loading my world, I got the following crash: https://pastebin.com/EJ26Jsi5
The crash persists when creating a new world as well.

I am using forge 14.23.5.2815

Embers is not supported, while Embers Rekindled is.

I'll look into trying to support both of them.

This issue is happening for me as well. I have All The Mods 3 pack installed with only 2 additional mods, ProjectE and ProjectE Integration and I get a very similar error to the one in their pastebin. Every new world in single player, or loading of a world in single player. I'm going to try hosting a server with these files and see if it will let me join..

So the server crashes too apparently, with the same error. Or at least very similar.

net.minecraftforge.fml.common.LoaderExceptionModCrash: Caught exception from ProjectE Integration (projecteintegration)
Caused by: java.lang.NoSuchFieldError: centerIngredient
at com.tagnumelite.projecteintegration.plugins.PluginEmbersRekindled$AlchemyMapper.setup(PluginEmbersRekindled.java:62)
at com.tagnumelite.projecteintegration.PEIntegration.serverAboutToStart(PEIntegration.java:135)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraftforge.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:624)
at sun.reflect.GeneratedMethodAccessor9.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.Subscriber.invokeSubscriberMethod(Subscriber.java:91)
at com.google.common.eventbus.Subscriber$SynchronizedSubscriber.invokeSubscriberMethod(Subscriber.java:150)
at com.google.common.eventbus.Subscriber$1.run(Subscriber.java:76)
at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:399)
at com.google.common.eventbus.Subscriber.dispatchEvent(Subscriber.java:71)
at com.google.common.eventbus.Dispatcher$PerThreadQueuedDispatcher.dispatch(Dispatcher.java:116)
at com.google.common.eventbus.EventBus.post(EventBus.java:217)
at net.minecraftforge.fml.common.LoadController.sendEventToModContainer(LoadController.java:219)
at net.minecraftforge.fml.common.LoadController.propogateStateMessage(LoadController.java:197)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.Subscriber.invokeSubscriberMethod(Subscriber.java:91)
at com.google.common.eventbus.Subscriber$SynchronizedSubscriber.invokeSubscriberMethod(Subscriber.java:150)
at com.google.common.eventbus.Subscriber$1.run(Subscriber.java:76)
at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:399)
at com.google.common.eventbus.Subscriber.dispatchEvent(Subscriber.java:71)
at com.google.common.eventbus.Dispatcher$PerThreadQueuedDispatcher.dispatch(Dispatcher.java:116)
at com.google.common.eventbus.EventBus.post(EventBus.java:217)
at net.minecraftforge.fml.common.LoadController.distributeStateMessage(LoadController.java:136)
at net.minecraftforge.fml.common.Loader.serverAboutToStart(Loader.java:854)
at net.minecraftforge.fml.common.FMLCommonHandler.handleServerAboutToStart(FMLCommonHandler.java:292)
at net.minecraft.server.dedicated.DedicatedServer.func_71197_b(DedicatedServer.java:268)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:486)
at java.lang.Thread.run(Unknown Source)

Should be fixed in version 2.2.0