Z (34 years old) gains his "Black Arm" epithet by using Busoshoku Haki. It was stated that all Marines with a rank of vice admiral and above can use Haki, so Z could also use this ability.
Z and Luffy battle with their Haki. Z and Luffy activate their Armament Haki, their arms turning a hardened black.
He eventually participated in his first battle four years later, in the G-5 Division. At the age of 28 years old, Zephyr realized that the Marines are not always heroes. Six years later, Zephyr had mastered Busoshoku Haki. For this reason, he received the epithet "Black Arm".
He also ate the Gum-Gum fruit, a devil fruit which has given him stretchy rubber limbed abilities, although at the cost of his ability to swim.
Coby has a high level of control over his Kenbunshoku Haki. He first awakened this ability during the Summit War. With the help of Kenbunshoku Haki, Coby was able to hear the voices of the people around him fading away, which implied that people were dying.
It's no surprise that Luffy possesses the power to use all three types of Haki, being someone who aims to become the Pirate King. In fact, Luffy has successfully taken his Armament and Observation Haki to extreme levels, making him a magnificent pirate in the process.
Z screams after losing his arm and almost all of his division. Twenty-three years after the death of his loved ones, Zephyr's arm was cut off by an unknown pirate with a Devil Fruit power, and his entire division was massacred with only Ain and Binz surviving.
In his past under Zephyr, Kizaru has a greatest respect for his former mentor only being warned for relying on his devil fruit powers too much. In the present for One Piece: Film Z, Kizaru still maintained his respect for Zephyr. In the final battle, Kizaru has no qualms to kill his mentor.
One Piece's Haki has fans questioning the physical changes that occur after use. According to Oda, haki is invisible but for viewers Oda did colour black so people can see it. Haki has slowly become one of the most-praised aspects of post-time-skip One Piece.
Zeff is the head chef and owner of Baratie. Before that, he was the captain of the Cook Pirates (in which he was known as "Red-Leg") until his crew was annihilated in a storm. He is also Sanji's cooking mentor and adoptive father, having taken in the boy after being stranded with him on a desert island for months.
As stated in One Piece Wiki, Haki are invisible. As stated in Anime and Manga Differences, Haki are made visible so that viewers can understand that Haki is being used. In the manga, those hit with Haoshoku Haki foam at the mouth after or while losing consciousness, whereas in the anime, they simply faint.
Those who have mastered the fourth form of Haki will be able to manipulate nature as they see fit. They can cause living organisms to grow rapidly or die rapidly (though not resurrect them), and make objects move with the force of their minds, akin to telekinesis.
Dragon is almost certainly going to be a user of Conqueror's Haki as well just like his son. In Marineford, Luffy's Conqueror's Haki was attributed to Monkey D. Dragon, meaning he is already implied to be its user despite not having used it so far. In the future, fans will certainly see him make use of this ability.
There are three major types of Haki: Observational, Armament, and Conqueror's.
According to Oda, Chopper is 17 years old (originally 15) and his birthday is December 24. When asked by a fan what the nationalities of the members of the Straw Hat Pirates would be if One Piece was set in the real world, Oda replied that Chopper would be Canadian.
Kid also confirmed that he had lost his arm in an encounter with the Red Hair Pirates but did not clarify that it was done by Shanks himself.
We know Luffy had Gear 4th during that time, he's had it since his training during the time skip.
The most plausible candidate is Edward Weevil.
Zephyr passed away today; he was 11 years old. He was euthanized early this morning due to complications from myasthenia gravis, and was surrounded by those he held dear – his siblings, his human family, and the many wild animals with whom he shared his life.
7/10 Edward Weevil
While Weevil's abilities remain largely unknown, he isn't known to have eaten a Devil Fruit, which is why he makes his way on this list.
Haoshoku Haki is a rare form of Haki that allows the user to exert their own willpower over others. This type of Haki cannot be attained through training and only one in several million people are born with this ability.
4/12 Armament Haki Subtype 4: Advanced Ryuuou
So far, only two characters have shown the ability to use it, Rayleigh being one, and Monkey D. Luffy being the other. Although Rayleigh seemed like an expert at using it, Luffy has only managed to use it subconsciously.