The Emerald Herald is this game's Frampt, which is really the only concrete piece of the story that I've been able to piece together naturally. You start the game with the goal of breaking the curse, and are told vaguely to "seek the king" and "find more powerful souls."
By the time you've done that, you've met numerous NPCs who forgot why they came to Drangleic in the first place, and I had by that point as well. I was actually really frustrated with the story in the game before I realized this; I felt like there was no direction and no clear goal. I realize now that might be intentional, which is pretty cool. Shanalotte just wants you to do her bidding.
The stuff I'm less sure about:
-Who/what are the giants? They're completely different from the DKS1 giants, both the giant humans and the monster giants. This is getting confusing.
-Who is the player character and why do you fall through what appears to be the abyss to get to Drangleic?
-Where is Things Betwixt and why is it called that?
-Where is everyone? Lordran was empty because everyone had left. A lot of characters in Drangleic talk about it as if there's still some form of society, but there really isn't.
-Why is there a chunk of broken Lordvessel in Majula's mansion basement?
-What the hell is the Throne of Want?
Stuff that I think is straight up stupid:
-Moreso that Dark Souls 1, this game really confounds the line between alive, dead, and undead. At first I thought the implication was that everyone in Drangleic got there by dying (dialogue with the Pyromancer, Cale, Creighton, the Blacksmith, and his daughter seem to hint at them all not realizing they died before getting here) but some characters can straight up die, while others are in the process of hollowing. Also there are ghosts, because, uh... hmm.
-This game relies too heavily on references to Dark Souls 1's lore, in my opinion. It really beats you over the head with the HEY THE FOUR BIG SOULS HMMM SORT OF LIKE BEFORE HUH thing, especially with the renamed souls in NG+.
-Again, the whole giants thing - there are like three different distinct groups called giants in this series now. It's not cryptic, just confusing.