First Wave S03E20 - Beneath the Black Sky

Foster encounters Xevallah, the mysterious stranger who rescued him from the Gua when he was a child. Xevellah teaches Foster the essential wisdom of forgiveness and prepares him for the final battle with the Gua.

Quatrain 22, Century 4: "When twice three years and twice again / Find secret skill in darkest hour / 'Tween blessed and cursed a third will come / Or world's consumed in battle's fire".