Whether or not Levi had ended up with some sort of community service (and, potentially, self-inflicted exile) it seems he's found enough time to visit the town hall, see Chloe's note, and then find his way here. He knows it's potentially dangerous, but he does want to help, and, well. Knowing that Chloe has a gun certainly helps, too. She won't be helpless if the creature somehow takes control of him again.

He doesn't have much of a green thumb, honestly -- or rather, never really had the chance to find out whether he does or not -- but deconstructing some cabins is definitely something he can do.

He stops a few meters away, watching Chloe for a while before finally resolving to announce his presence.

"You were looking for help."