When Hattori Hanzo's treaty is relinquished, Tenzen leaps at the chance to seek and destroy the Kouga Clan. While Oboro is standing Chief, Tenzen acts as the Iga ringleader for the Kouga strikes. Without her consent, he gives his assassination orders with one goal in mind...conquer the Kouga before their scroll gets in their hands.
But even he knows this may come back and haunt them in the long run. Still, Tenzen roughs up his enemies, wreaking havoc wherever he goes. Seemingly resilient to any harm done to his body, Tenzen's able to survive due to his most secret ability.
(Source: FUNimation's Official Basilisk Website)