As the title say i wonder what have you as a player or as a GM thrown at your group that would/did break them ( end game stuff )

Like have anyone thrown the kraken from Tome of Blood

Recreated the Skull Harvest

Thrown high end demon princes or greater demons at a low-mid game party

Personaly worst i fought was a bunch of mechanicus dudes and a Onager deamon engine of wich our heretek forced it into lava.

Best Troops players got:

• Mutiator - rarely used
• pyromancer coven - rarely used
• Tzeench daemon bound Silvertower - got for terror tactic/ground support cant be fielded with nurgle daemon-engine
• Nurgle daemon-bound defiler - actively used good for terror tactic/infantry
• Warp Talons - most effective unit they hired
• Chaos Space Marines - untrustworthy, always whining ,irresponsible bunch of super-soldiers just like the player characters....
• Human disciple of chaos, Renegades, Pirates, Lost and Damned troops - numerous devoted followers ideal for mechanized warfare (thanks, jets, artillery, etc) dies very quickly

Worst enemies they stands against,

• Greater daemon of Tzeench, Lord of Change: Oba 'mhara
• Sorceres, chaos spykers
• Khorne daemon engine Brass Scorpion
• Rak 'gol mobs
• Rubric Marines
• Phase Assassin
• Imperial Knights