Zabimaru's spirit takes the form of a two people: an adult woman and a small boy, attached to the female's waist by a black chain that is connected to a collar on his neck. The young boy has blue eyes and jaw-length crimson hair. He wears a robe similar to a priest's that is cut short to reveal much of his stomach, with long sleeves that extend well past his hands. He has a snake's tail on which he often balances on to sit in the air.
(Source: http://bleach.wikia.com/ )