He should always be present at all 3 locations.
I think I had the same issue as Kai on one of my characters, forgot which. I met him in all three places but didn't join the covenant right away. Came back later to do that side-quest and decided I'd do the Black Gulch portal first, since it's the most annoying to reach
(and to do, as well, with those turtles and pyros) and wanted to get it out of the way, but
Ingward Grandahl wasn't there. I was pretty mad.
I went to Drangleic and he was there, did that dungeon, came back to the Black Gulch and there he was. Weird shit.
I think you get greedy in a Souls game sometimes due to the audacity of the bird versus the elephant. The enemy is so big, often lumbering and slow. But they can abruptly react with surprising speed. And it seems a Souls trademark that enemies with OHK moves have surprising reach and angle coverage.
True. And sometimes getting greedy
does work. You
can,
sometimes, get that last one hit by using what's left of your stamina to finish off the monster (which you wouldn't do in the middle of the fight because that'd leave you too exposed or whatever) and it works. But when it doesn't, when that sliver of HP the boss had is not as small as you calculated and you needed an extra hit after all, oh boy, does the game love to punish you.