Wow... that crash report is so generic, that I can say, will stop the crash from happening is to remove Forge itself. Which... is not the solution you're looking for.
(It does not reference any mod specifically.)
Could you try starting a new world without Natura (creative mode) and going to the end there? Does that
not crash your game?
If so, I may have another solution for you, which involves deleting The End from your save file and editing your Player Data, for you to be in the Overworld or wherever you were before again.
If not, there's two things you can do right now:
1. Install the Openeye mod, reproduce the crash and hope that Openeye, with its huge database of crashes, is able to point out a limited number of mods that could be the cause of this crash.
2.
Make a backup before you try this: Remove half of your mods (make sure you don't remove dependencies/coremods for the other half of your mods just yet) and try to load up the game and go to the end. If the game crashes, remove half of those mods again and repeat. If the game does not crash, the mod that is causing the crash is in the half you just removed, so install that half again and remove the other half of the mods and repeat just as long as you find the one mod responsible.
I know this can sound slow, but removing half of the mods every time actually makes you solve this problem faster, by cutting your MC startup time in two with every stage AND halving the number of suspects with every stage, Whereas going through all mods one by one, may cost you a lot more time, especially as the packs get bigger.
Caution: because your crash may be specific to your save file, you may have to reset your world to the version you back-upped, with every restart of Minecraft.