Link to Crashlog: https://pastebin.com/bKqH9fx2

Trying to set up a custom mod pack, was going smoothly up until recently as the WorldLoader screen, (the one that appears when you select "create new world" in Singleplayer), was clicked to test that it was running fine.

Most Recent Few mods added were;
- Create (+ its addons)
- Immersive Weathering [Forge]

I've tried all I could think of since loading up the game worked fine and I've never had this issue before. 

Any help is appreciated.  

Go to the config folder and check the iceandfire config files

Set "CustomMainMenu" to false

Unfortunately, the crash still occurs. 

And without Iceandfire?

Issue was TerraFrimaCraft, I went through each mod one by one disabling them. Thanks for trying to help though!