You and Thatch raided the mayor's manor in a small town, resulting in a mob of gun firing villagers. Ace was fending off some villagers with his flame logia when he found you with a chest in hand, so you guys ran to an empty warehouse to hide for a bit. After a bit of lock picking you manage to open the chest to find two devil fruits.

Ace: "Woah.. That explains the angry gun firing mob. When devil fruits get involved people become deadly.."

(Make up both DF and decide which one you'll eat.)