It's been a while, and I'm not sure exactly who you are referring to......was it a guy in the lake? Anyways, I played as a STR/DEX character, wearing heavier armor for poise. Almost all the invasion NPCs and quick mini-bosses I would just roll in then continuiously hit them until they were staggered. It makes the agile enemies trivial. The difficulty with this build is on bosses, since you can't really stagger most of them reliably.
If you are using a DEX build, then you will probably just need to git gud and learn how to dodge and counter, maybe parry.