speed x100Hero and oases
Your hero is needed to capture oases, and fighting oasis animals is a safe way to earn hero experience.
To capture an oasis, your hero must be in a won normal attack that kills every animal. See Capture an oasis.
Each killed animal gives experience equal to its upkeep (Rat 1 up to Elephant 5).
Bring enough troops: the hero loses health equal to the army's losses.