White Zetsu Army

The White Zetsu Army consists of 100,000 copies of White Zetsu, which serve as Akatsuki's main military strength during the Fourth Shinobi World War.

Background
According to Sakura and Shizune's research, the White Zetsu Army soldiers are clones of Hashirama Senju. More precisely, they are the hybridized result of the First Hokage's cultivated cells infused within certain plants that serve as mediums. Tobi created the Zetsu army clones using the chakra of the first seven tailed beasts he had sealed within the Demonic Statue of the Outer Path, along with a living clone of Hashirama. The resulting White Zetsu are created and stored beneath the Mountains' Graveyard. After Kabuto Yakushi captured Yamato, he used his studies of Hashirama's DNA and Yamato to enhance the army's strength.

Personality
These clones have shown some level of intelligence, similar to other clones. Although they were seemingly fighting mindlessly against allied shinobi during the daytime, the clone who had transformed into Neji Hyūga using his Substitute Technique, was noticeably scared by Sakura Haruno when she threatened to beat him and showed shock when she deduced how his technique worked as well as the tactics of the Zetsu army's night assault. They were also visibly angered when they realised that Sasuke had killed White Zetsu, whom they refer to as their original.

Appearance
Unlike the original White Zetsu and the clones he produces, which possess incomplete bodies, they have complete heads, as well as properly defined right arms and legs. After Kabuto used Yamato to further enhance their abilities, the Zetsu clones gain small spikes that protrude from their shoulders and back. These Zetsu, however, lack the Venus fly trap-like extensions that the original had, and have what seems to be cracks all over their bodies. They also have a zig-zag pattern running from their diaphragms down to their groin, and also down each leg reminiscent of the originals' fly trap-like extensions. These serrations are later shown to be able to open in a similar manner. When the Zetsu are first depicted in coloured manga illustrations, they appear not white, but light-green. In later depictions they appear even more green in colour.

Abilities
As the main force of Akatsuki's army, the White Zetsu are presumably adept at combat. With Kabuto's use of Yamato to increase their strength, they are presumably even stronger than before. Like the original Zetsu, they are able to use Mayfly to travel underground. They are also extremely durable, able to survive two attacks from Sakura, as well as Neji's Gentle Fist Art One Blow Body, and seem to have limited regenerative abilities. They can open their bodies in a Venus flytrap-like manner to trap their opponent and absorb their chakra. Like the original White Zetsu, they are also able to use the Substitute Technique. In the anime, it was shown that they can also extend the points of their flytrap-like openings and use them to impale enemies.

Their capacity to absorb chakra serves a more sinister purpose: to use the Substitute Technique to take on the appearance and chakra signature of the person they latched onto. With this ability, they can gain the trust of the copied person's acquaintances, deceiving even the best sensors. Such an ability is perfect for espionage and covert assassination. These Zetsu are also able to merge together with each other to form large, deformed versions of themselves that resemble fly-traps even more, which seems to make them somewhat more resilient. Due to the fact that they were created through cultivation of Hashirama Senju's cells, Sakura states that they can also use Wood Release, albeit on a weaker scale. A downside to their genetics is that, once they come into contact with a powerful concentration of Yang-natured chakra, it affects them directly, causing them to turn into trees.

They also seem to be capable of breathing in water, as shown in their first appearance, when Tobi kept them in storage underwater in an underground pool.

Confining the Jinchuriki Arc
After creating an alliance with Kabuto, Tobi leads him underground and shows Kabuto his army of 100,000 White Zetsu clones in an underwater cavern beneath the Demonic Statue of the Outer Path.

Shinobi World War Arc
Once Tobi finished his preparations for the Fourth Shinobi World War, he had the Zetsu army mobilise to fight the Allied Shinobi Forces' 80,000-person strong army. Because of the size of their forces, Tobi has the Zetsu travel below ground, to be led from above by himself to hide their numbers. This was discovered by Muta Aburame and is reported to the various commanders. The Second Division, led by Kitsuchi, as well as elements from the Fifth Division, unearth and attack a detachment of 20,000 White Zetsu travelling directly underneath them. While fighting the Allied Shinobi forces, they began to overwhelm them, allowing several thousand White Zetsu to pass through underground.

Then, off the coast of the Land of Lightning, several thousand White Zetsu appeared along with Kakuzu, Hizashi Hyūga, Asuma Sarutobi, Dan, Kinkaku and Ginkaku to attack Darui's First Division, forcing the Allied Shinobi Forces to change their strategy to meet this threat. By the end of first day of battles, the army had already lost 50,000 out of its 100,000 Zetsu, leaving Tobi's army at half strength.

During the night, Zetsu Army soldiers used the Substitute Technique to sneak behind enemy lines disguised as allied shinobi, and killed various members of the Allied Shinobi Forces. After Sakura Haruno discovered and stopped one of them, who had transformed into Neji Hyūga, the technique was deduced and it was reported to HQ. When Naruto and B confronted several of these clones, due to Naruto's Yang chakra and the nature of the Zetsu, when he attacked them they all turned into trees. This was due to the fact that because they were made from the First Hokage's cells, they resonated with the life force energy of Naruto's Nine-Tails Chakra Mode in a similar manner to the way Yamato's Wood Release did in the Tailed Beast Temple. Even after they merge to try to become more resilient, Naruto merely cut them in two and crushed them beneath Gamahiro.

Naruto eventually sent his clones out to the different battlefields and, using his ability to sense negative emotions, was able to locate the remainder of the disguised White Zetsu.

After the second day of war, thanks to the addition of Naruto's efforts and his new-found ability, the majority of the White Zetsu clones were eradicated. However, small factions survived and were ordered to seize Killer B and Naruto before their comrades could reach their location. When Sasuke escaped the Mountains' Graveyard, he encountered one of these factions, who demanded to know why he left the hideout. Upon coming to the realisation that he had killed the original White Zetsu, they attacked him. Choosing this time to test his new powers further, he slaughters most of the Zetsu before using a genjutsu on a surviving clone to discover that Tobi has waged war and that the Allied Shinobi Forces were moving to aid Naruto in his battle. He then killed the clone, as well as another that was attempting to escape, before heading toward the battlefield to kill Naruto himself.