haki zoro

Haki

It was stated by Luffy that Zoro possesses Haki, when discussing it in the context of members of his crew who could fight Caesar Clown, a Logia user. Because Law was referring to the ability to coat themselves in armor it confirms Zoro as a Busoshoku Haki user. When fighting Monet on Punk Hazard, Zoro was able to slash her cheek, displaying the use of Busoshoku Haki.
Although it is unknown if he can use it, Zoro knows about Haoshoku Haki, something he (with the rest of the crew) had not shown any knowledge of in the first half of the series. He, alongside with Sanji, has commented on Luffy's ability to passively knock out half of Hody's men, stating that if Luffy could not at least do that much then he would have had to step down from being captain.It was hinted that both he and Sanji have Kenbunshoku Haki when Luffy asked the pair if they could sense a "wild animal" in the Ryugu Palace, which they both answered that they could.

Asura

Asura's three heads, six arms and nine swords.

During his battle against Kaku, Zoro has shown a new technique called "Asura" which gives him the appearance of having six arms and three heads, like the deity of the same name. He is also surrounded by a dark aura while in this state and the first time he achieved it, the ground shook and numerous holes appeared in it. This ability allows Zoro to utilize nine swords in combat, and is usually used for a very powerful final blow. What this ability is, how Zoro attains it, and the exact nature of this attack are currently unclear, but Kaku suggested it was an illusion created by Zoro's spirit.

Zoro's Swords

Zoro's current katana.

During his adventures, Zoro has acquired many swords. The three he currently uses are:

1. Meito; Wado Ichimonji (formerly belonged to Kuina)
2. Sandai Kitetsu (formerly belonged to Ippon-Matsu)
3. Meito; Shusui (formerly belonged to Ryuma)

Former Swords

For one reason or another, maybe as a demonstration of his skill because he can use any sword he must at any time, Zoro has one or more of his swords destroyed, removed from his possession, or incapacitated in some way:

1. Katana x2 (both were destroyed by Dracule Mihawk)
2. Johnny and Yosaku's swords (returned to them after the battle)
3. Meito; Hana Arashi (Sogeking handcuffed to Zoro holding on to Yubashiri. It stopped being used when Sogeking was unlocked from Zoro)
4. Meito; Yubashiri (formerly belonged to Ippon-Matsu, destroyed at Enies Lobby by Shu, now resting on Thriller Bark)
5. Marine cutlass x2 (the first one was destroyed by Shu, and the second one was consequently left behind after the immediate battle at Enies Lobby)