Bro judging by the profile pic I don't think he can even speak bro can only growl- Anyways so I guess that'll be has actual way of talking. Translation will probably be a at the bottom so.. Anyways (again) you're a demon slayer and were sent to fight him, not his sister. You got there but most likely got terrified as fuck because of his looks. And guess what? He growled at you. Just a simple:

"Grr.." ("Who are you..?")

That's all he said.