You're killing the wrong guy. Don't kill the Last Giant, you wanna kill the Giant Lord. They're different. The Giant Lord is in one of those Giant's memories, its the one in the forest of the giants by the bonfire through one of those doors that requires the king's ring to enter. You have to summon Benhart for every fight you do, and he can't die or it doesn't count. You should only have to kill him like 3 times I think? I just did it and it worked.

That is a very common Microsoft issue unfortunately you can choose to wait 6+ months for them to fix it(if they know about it) or report it to them and still wait the same amount of time

Benhart is pc all the way, he finds you unworthy because you are using a console.

Late to the party, but in some from soft games it might help to put the gear that you got in the item box at bonfire, and then add it back to your inventory.
I am not saying that it will definitely work here but it has worked for me on other quests where I did not get the achievement.

"Benhart is pc all the way, he finds you unworthy because you are using a console" Hahaha

You're an idiot pos. Why would trust a little white kid.

19 jun-racist

deepest lore

deepest lore

Screw off anti-white!

Did you summon him for the fights?
I am guessing you did.