Through Fire and Fear / Four x male oc / divergent series

As the Prior family navigates the rigid expectations of Abnegation, Elias Prior - Beatrice's older brother - wrestles with his own sense of identity. When the Choosing Ceremony forces a decision that changes their lives, Elias finds himself in Dauntless alongside his sister - and unexpectedly, in the orbit of Four, a man who challenges him in ways he never anticipated.