Note that there is an internal cooldown on Blood Scent of 1.25 seconds.
Note: The ability lets tankier characters group up to force Warwick to distribute the damage. Instead of Warwick getting a bonus for a target being isolated, a la Kha'zix, Warwick gains better team fight presence by nonetheless applying on-hit effects to targets affected, allowing him to reduce Armor and Magic Resist effectively with a Black Cleaver. The range is shorter than the old Hungering Strikes by a slight amount, and the cone is relatively narrow.
This effect doesn't stack, but in combination with the passive lifesteal and the bonus healing form Blood Scent's stacks, this would be Warwick's primary Jungling tool, since he can Mark Blue or Red buff.