I made opponent head health to zero. but still get attacked. how can I win battle unharmed?

I'm trying to understand the core mechanics of the game and there are parts of it that feel opaque to me. I think I get that if an enemy has a long time to strike, like 100+, and you have a defense that will only take 50, doing that will give them plenty of time to change their attack and hit you. However I have had it so that their attack will hit in 60, and my defense would take take 55, yet they were still able to change their attack before it hit to get around my defense. Is there some stat you can v...

Ive noticed that, with the same speed stat, some stances are simply faster than others. What are the fastest stances? Strongest? Is there a perception difference?

:(

Death