Sons of Sorrow by Nazri Noor

The Tears of the Ocean. The Heart of the Flame.
Lochlann Wilde is preparing for his final challenge: entering the Oriel of Fire, the most dangerous of the elemental dimensions. Acquiring the essence of fire will score him another powerful guardian, as well as complete Aphrodite’s amulet.
But the world outside the oriel has its own challenges. Sylvain has discovered something difficult about his heritage. Aphrodite keeps dropping unsettling hints about Locke’s true nature, too.
Most pressing of all is the mystery of the parchment that cursed Queen Aurelia to begin with, the only clue that may lead to the truth about the Withering. Who is behind it? Why did they engineer the plague?
And how can Locke and Sylvain stop them from infecting the cosmos?