Sabo eats the Flame Flame Fruit in One Piece Episode 678. This episode is titled "The Fire Fist Strikes! The Power of the Mera Mera no Mi Returns". In this episode, Sabo enters a competition hosted by Doflamingo, who was trying to lure the Straw Hats since they foiled his plans in the past. Luffys goal was to win the tournament and consume his brother's Ace Devil Fruit, but he never knew that Sabo wanted to achieve that goal.