The Shadow Leopard is a rare Clouded Leopard that can be found in the Kyrat Fashion Week quest at KEO Logging Camp (coordinates: 417, 754) in Far Cry 4 they are based on the Sunda clouded leopard in Indonesia. The Shadow Leopard must be killed with an assault rifle, and resides close to the small, cliff-overlooking, cave. Consider taking a signature weapon, rather than relying on the stock AK which will be provided. Its skin provides the final ammo bag upgrade.
Interestingly, the leopards that accompany the Shadow Leopard are Snow Leopards, not Clouded Leopards.