Yeah, right now I'm betting it's Loki.
And it's entirely possible that the Strawhats came with Loki of their own accord just don't remember any of it. Because they were all stinking drunk. They might have just left the others on the ship because they were already sleeping. They were fine. They'd pick them up later.
I feel like Loki's probably going to be very confused about why they're all confused about where they are.
And here's the thing, we know ONE thing about Loki, and it's that he got rejected by Lola. Loki is probably something of a romantic. So, I honestly wouldn't be surprised if he has eyes for Nami. And if Nami WAS hallucinating due to the Green Fairy Absinthe...who knows what she said or what she was seeing at the time. It's possible Nami told Loki that she'd marry him, when she thought she was talking to a giant pile of money, or something ridiculous.
Loki is pretty young for a Giant, at 63 years old (according to the wiki). He's technically the youngest named Giant we know. The only Giant who's younger who we've seen is Shank's Fanboy at the bar. Giants age around 3 times slower than humans. So, Loki is around 21 years old. He might not even be old enough to drink quite yet in Giant years, we don't know for sure. So, between being young-ish, impressionable, and possibly having Lego powers...chances are Loki's kind of a nerd. At least by Giant standards. I wouldn't be surprised if he's more bookish than the other giants. Maybe he's been studying the Void Century with Saul?
It's possible that this chapter is called "Taking Responsibility" partially because Loki is going to "take responsibility" for something that happened while Nami was drunk. A "She kissed me, now I HAVE to marry her" type of deal or something.
If this turns out to be true...I'm going to really feel bad for this guy. This poor guy. Loki probably just wants someone to share his love and love of Legos with. Can any of us say different?
...I'm probably wrong, but just imagine if I'm right.