Monkey D. Luffy, who finally managed to reach Laugh Tale and was only one step away from attaining One Piece, got transported into the world where Titans live with tyranny and Humanity was on the brink of extinction. How will an optimistic pirate lives in an unfamiliar world? How? Meat. The Future Pirate King only needs meat to survive. On the other hand, Eren kept getting involved with Luffy as he kept going forwards on his own without knowing a thing about this world. Constantly thinking that he needed saving, soon enough, Eren saw Luffy's true strength.