I countered a {Bloodbraid Elf} but was told that his cascade ability are still in the stack. I always tot that all creature abilities should only trigger when it comes to the battlefield?
It says in the rules text: "when you cast this spell"
You can't counter a spell unless it has been cast.
If the rules of cascade said: "when target permanent enters the battle"
Then it would be when the creature reaches the battle field
Cascade is a "when cast" trigger, not ETB. So yes, this is actually true - if you Counterspell a cascade creature/spell, the cascade still happens.
RESOLVED