Originally I had Ace as Wirt but then I was thinking. What if Sabo was Wirt and Ace was the woodsman. 

Plot twist, Ace is their dead brother they can’t seem to remember what with being stuck in limbo. But of course Ace recognizes them and does what he can but Sabo is super suspicious cause this guy seems so familiar but he can’t seem to ever place it. Not to mention aside for the guy seeming almost too eager to help them, he keeps saying stuff like they’re not suppose to be here or they don’t belong here.

Well cue a giant monster and Ace tells them to run as he buys them time. It’s not like it can kill him anyways. Not that Luffy and Sabo know that but they run. And that is where they run into Marco who is stuck in a trap and in return for freeing him he takes them to the small town. Cause if anyone knows how the boys can get home it’s his father. 

Whitebeard take the place of the huge pumpkin guy who tells them that they really don’t belong here (wtf that’s what the friendly wood guy said). But he tells them that if they stay on the path and avoid the deep woods than they should find their way back.

Marco joins them cause it turns out that the giant guy just didn’t have a weird bird son, Marco is actually cursed. Along the path is the house of Big Mom who has scissors which can change Marco back to human. He wants to see if he can reason with her and exchange them for something. (womp womp, for what no one knows but her)

Teach is the monster who had tricked Ace into thinking he needed to keep his lantern alive or he’ll disappear forever. To disappear and be permanently forgotten. What he doesn’t know is that it’s actually keeping Luffy and Sabo there, Sabo especially who are lured unknowingly by the presence of the brother they’re still so heavily grieving. Which is why they keep deviating from the path without meaning to. (Ace is horrified to realize that the oil he uses to keep his flame lit was fueled by lost souls at the end.)

That was all I thought up cause I fell asleep but man, I think it’s a good au, lol.