Genkotsu was a member of the Snakeroot, an organization with complex ties to the Hand. The organization were reportedly successors of an Inner Circle within the Hand that somehow became independent. In modern times they still had influence over the Hand or at least a faction of it. Genkotsu himself was a “holy” man who sought peace for much of his life. Somehow his quest ended with him as the chief torturer within the Snakeroot and among their leading magic users. He precided in the ceremony which created Erynys.
He faced Elektra in battle and was killed but then resurrected by his teammates. She did not go easy on him in their next encounter. She crashed a truck into him, costing him the use of his back and legs. The Snakeroot decided to let him die instead of ensuring the survival of a paralyzed body.