When you speak of Black Zetsu Halve, you speak of the White Zestu Halve. Why I say this? Both Black and White Zetsu are both one-being. One is unknown which is the Black Zetsu Halve and the White Zetsu Halve was said to be created from Hashirama's cells (or DNA/Genes). The last scene of the "two" characters - when split from the conjoin body - Black Zetsu was performing Guerrilla Tactics which turn into a full-out battle against the Fourth Mizukage Mei and her squad, later being bisected by Chōjūrō's Hiramekarei; and White Zestu was looking over Sasuke within a cave. White Zestu would soon be killed by Sasuke whom tested his "new power" on White Zestu.
