Fairy Tail chapter 513 spoilers: The battle between Sting, the White Dragon, and Larcade will boil down to its conclusion. Natsu's anger towards Zeref is still brewing, Anna Heartfilia's role in the war.
Chapter 512 Recap:
-Sting, thanks to the power lent to him by Rogue, was finally able to fight with Larcade toe-to-toe. Not only did he resist the sexual desire, but he also stopped his comrades from eating one another.
Larcade seems impressed that Sting was able to go through two of the three ultimate human desires. However, he warns him that he cannot resist the third one, which turned to be sleep. Larcade brags that no one can go against their desire to sleep, not even the mighty Acnologia. That's why he has no doubt he's the only hope in stopping the dragon once and for all.
"Sting and Rogue are saying Sting's powers can absorb Larcade, and Rogue's shadow back can destroy him. Larcade says no matter how many people come together, no one can fight the final desire of sleep, in this case eternal sleep for them.
He says no one can go against their desire, not even Acnologia, which is why he's the ultimate mage to go against him," Fairy Tail chapter 512.
-Just when Sting was about to succumb to Larcade's incantation, Kagura pulled him down with her gravity magic. This allowed Sting to launch a counterattack against Larcade, piercing through the Spriggan 12 mage with his White Shadow dragon attack.
-Meanwhile, Rogue revealed to Natsu the true nature of his scarf. Aside from it's made from Igneel's dragon scale, the scarf is apparently made by Anna Heartfilia, the first celestial mage and Anna's ancestor.
Natsu whispers he'll defeat Zeref no matter what. Happy is concerned with Natsu, advising him to give up on his goal or else he'll die along with the black mage.
-Everything is life. That's why friends... family is irreplaceable... Will be continued in chapter 513: Flower