Zetsu. one being?
Zetsu is an interesting character and not just in appearance but in personality as well. We know Zetsu has split personality and both can interact with each other. One side seems serious (black) as the other is the opposite (white).
There are some things that just happen to confuse me and I want to bring them up so we can discuss it.
Zetsu first appears as a superior to Tobi/ Madara as seen below;
NarutoBase.net - Naruto Manga Chapter 280 - Page 19
Unfortunately, I don't know which half is saying what but I'm assuming that the black half is saying that they should let him in while the white half is commenting on how it's not easy.
When Pain is finished fighting Jiraiya, Zetsu appears again and both seem to differentiate in thought.
NarutoBase.net - Naruto Manga Chapter 383 - Page 14
I reckon Zetsu (both sides) knows that Tobi is Madara as Pain says, "Right after Madara ordered me to capture the Nine-Tails". The white half wants to go watch the Konoha fight while the black half already knows about Itachi vs. Sasuke fight and wants to go there instead. Unless there was some sort of mistake, it seems to me like the black half knows much more about Madara's plan than the white half. During Itachi fight, the black half seems to be well aware of the legendary items that Itachi possessed as well as the Sharingan techniques used by Itachi.
NarutoBase.net - Naruto Manga Chapter 392 - Page 14
NarutoBase.net - Naruto Manga Chapter 393 - Page 9
Black half seems to know Itachi was going to die. He knows that Itachi wasn't fighting at his best and he even denies the fact that the reason Itachi was coughing up blood was because of over using his Sharingan.
NarutoBase.net - Naruto Manga Chapter 394 - Page 5
NarutoBase.net - Naruto Manga Chapter 394 - Page 6
After Itachi's fight, Zetsu reports back to Madara and the white half seems to know about Madara's plan now or so it seems.
NarutoBase.net - Naruto Manga Chapter 395 - Page 15
Madara and Zetsu talk but seems like the black half is doing all the talking. Seems like Zetsu has been working with Madara for some time, "It's been so long".
NarutoBase.net - Naruto Manga Chapter 404 - Page 16
It seems he was also aware of how Naruto defeated Pain;
NarutoBase.net - Naruto Manga Chapter 453 - Page 14
Again, the black half is having a chat with Madara and he seems to know about Gedo Mazo, etc.
NarutoBase.net - Naruto Manga Chapter 453 - Page 17
I think Zetsu has a big part in Madara's plan. I think Zetsu is the one who provides Madara with his missing arms and body parts and he gets these parts by consuming others. I'm pretty sure Zetsu has been helping Madara for a long time. Zetsu is playing a key role in the survival and regeneration of Madara's body that is Tobi. What do you think the purpose of Zetsu is other than being a spy/ his spore/ cloning techniques. Every Akatsuki member had some sort of back ground story, what do you think Zetsu's is? Do you think the Black half and White half are two beings who have the ability to combine when needed or the opposite?
We won't know until more information on Zetsu is revealed but we can only speculate for now ( :.