Bleach: Renji’s Zanpakuto and Bankai, Explained

While still only the Lieutenant of Squad 6, Renji Abarai is easily Captain-class in strength, and is one of the few Lieutenants to have access to a Bankai in Bleach. That said, the true nature of his Zanpakuto, Zabimaru, was only revealed to him after he did a great deal of training.