How am I supposed to kill Black Dragon Kalameet?

Hi, I have been trying for about the whole day now to defat kalameet but nothings working, there was a point I got him down to 2 bars but he killed me first, I’ve been using the +5 black knight sword but I found it was to slow so I’ve tried some faster weapons but they are all way to low damage and it would take me ages to inflict real damage on him. I’ve tried using pyromancies and other spells but he always seems to end up getting me, I’ve tried so many different ways of attacking idk what to do, anyone have suggestions?