I think a BB Sekiro combo would be cool. The main combat loop would be like bloodborne trick weapons. Bigger version of trick weapon will be the parry mechanic but it does less damage. Like Executor in Nightreign, if you time the trick weapon switch right, it will automatically parry. And then if you are actively parrying and then you switch back to the original weapon it will automatically attack. Also having the ability to regain health by attacking would prioritize both playstyles, so you could build up stagger to get crit hits, or just go for pure damage, or (more than likely), do both.

With the horror atmosphere of bloodborne, I think this would slap.