Oathkeeper

Oathkeeper is a novel in the Bravelands series, set among the animals of the African savanna. Erin Hunter is the pen name of a team of writers.

The Great Herd has finally come together against Titan, a rogue lion who has grown so powerful that even Fearless cannot defeat him alone. Fearless has vowed to avenge his father's death, but vengeance by himself will not be enough.

Thorn may have a plan that could bring about Titan's downfall. Before it can be carried out, the animals of Bravelands must decide how much they are willing to risk and who they are prepared to lose.