Pharmakon — Sunshine Somerville

We only get a few second chances...

In Phantasya's supernatural paradise, the Warriors and their friends hope to rest for a while. Soon, however, trials and revelations arise for each Kota Warrior. Rave and Arctos travel back to Ebon to finish a mission they thought was over, this time with a shocking ally. Amu, struggling to find her place again, teleports to Rowen and discovers a secret hidden since Earth. Left on Phantasya, Kynacoba and Galcon fight a devilish enemy who could lead the natives into horrific rebellion against their Guardian.
Meanwhile, the isolation of Trok's immortality begins to take its toll. Knowing how this future ends, he must do what's best for everyone involved. But Phantasya is a world fated to test man's faith, and the Phantasyans aren't the only ones plagued by doubt.
How do you best fight a losing battle? The more the Warriors discover, the trickier their choices become.

Pharmakon is Book 3 in The Kota Series, an epic, 4-novel Science Fantasy series that features superheroes, alien planet colonization, time travel, a dystopia or two, and the supernatural battle between Light and Dark.