From Sonic Retro
The Deadly Six (六鬼衆 Rokkishū, lit. "Band of Six Oni") are the primary antagonists of Sonic Lost World. They are a group of six menacing creatures known as Zeti who are natives of the Lost Hex and enslaved by Dr. Eggman to do his bidding. Due to Sonic's recklessness, the Deadly Six rebel against the doctor and attempt to destroy Sonic's world using a machine that extracts life energy from the world below and use said energy to make themselves stronger, but in the end they are defeated by Sonic and their plans are foiled.
Based off of Japanese demons known as "oni", each of the Zeti have ogre-like appearances and come in various shapes, sizes and colours, and commonly sport features such as claws, spiky collars and horns. They all have the innate ability to manipulate magnetic fields, which in turn allow them to control robots and other kinds of machinery, which they do to Eggman's Badniks once they break free of his control. The Cacophonic Conch serves as a natural inhibitor to their powers; however, its effect is very excruciating to the Zeti, causing them great pain when they hear its sounds. Not much else is known about their origins. There are presumably other members of the Zeti species elsewhere on the Lost Hex or in the wider Sonic's world, with Zomom mentioning his mother supporting this theory, but the Deadly Six are the only representatives mentioned or encountered.
The fate of the Deadly Six at the end of Sonic Lost World is left unclear, as each of them disappear after their final defeat in the Wii U/PC version (Zazz, Zomom, Master Zik and Zeena disappear in a puff of smoke, while Zor and Zavok perish in lava). However, Eggman vows to try and control the Deadly Six again after his defeat, which would suggest they somehow survived, and they fly away in the 3DS version instead. Their reappearances in later games such as Sonic Runners suggest that they did survive after all.
According to Takashi Iizuka, the Deadly Six were intended to bring a "sense of danger and humor" to the story of Sonic Lost World. However, the Deadly Six are infamous for being some of the most unpopular characters among fans of the series. They have been criticized for having boring, one-dimensional personalities, designs that make them look out-of-place in the series, lackluster boss fights and very little explanation to their species or backstory.
Zavok is the leader of the Deadly Six, often referred to as the "Master of Chaos" and sporting a sinister red color scheme with cyan eyebrows and large fangs. Zavok is merciless, serious and cruel, often deploying graphical threats of death and destruction and showing little tolerance for failure. Accompanying his brutal qualities, he keeps a very calm demeanor and has a penchant for quick-thinking, knowing well how to manipulate others and using a situation to his advantage, which is everything you'd expect from a leader. He is fought as the boss of Sky Road.
He also appears in both versions of Mario & Sonic at the Rio 2016 Olympic Games as a playable guest character exclusive to Boxing, and in Sonic Forces as one of the illusory villains created by Eggman and Infinite.
He is voiced by Travis Willingham in English, and Joji Nakata in Japanese.
Zazz is a very tall and very lanky Zeti with a vibrant pink body, purple horns and a gaping mouth with a long tongue. He is nasty and incredibly destructive to the point of coming off as rather feral, boasting a very unpredictable attitude that makes this metalhead very dangerous to approach. He loves to pick a fight and run wild more than eating three meals per day, and holding him back from fighting will send him in a rage, and so will showing him disrespect. He is fought as the boss of Windy Hill.
He is voiced by Liam O'Brien in English, and Yutaka Aoyama in Japanese.
Zomom is the largest of the Deadly Six, sporting a very obese orange body, red horns, stubby legs and a large mouth. Simply put, Zomom is a glutton who will eat just about anything or even anyone, and simply mentioning food near him will drum up his appetite. As expected from a character of his size, Zomom isn't very bright nor is he very quick. He is also very sensitive about his size, getting hurt emotionally whenever somebody calls him "fat". He is fought as the boss of Desert Ruins.
He is voiced by Patrick Seitz in English, and Chafurin in Japanese.
With a short blue build, yellow horns and long moustache, Master Zik is the oldest member of the Deadly Six and the group's founder. He took Zavok under his wings and trained him, teaching him all he knows, and making him the leader upon founding the group. As an aged mentor, Master Zik keeps a calm and confident composure, and is never fazed by any of Sonic's insults or taunts. He is fought as the boss of Tropical Coast, and is able to use his powers to manipulate fruit to attack Sonic with.
He is voiced by Kirk Thornton in English, and Mugihito in Japanese.
Sporting a feminine build, green skin, long hair and a single pink horn, Zeena is the only female member of the Deadly Six. She is a very vain and selfish woman who utterly lacks initiative, and seems to not care about anyone else, preferring to spend her free time maintaining her beauty, which she is very protective of. It's only through motivation from Zavok that she bothers to get the job done. She is also very fashion-savvy, as she will not hesitate to criticize others for their fashion sense. She is fought as the boss of Frozen Factory, capable of producing a green whip-like energy beam to swing snowmen.
She is voiced by Stephanie Sheh in English, and Yumi Toma in Japanese.
Zor is the spy of the Deadly Six and one of the most dimunutive members, sporting a slouching white body with purple hair and cyan horns. He is one with the shadows, both physically and mentally. Physically in that he is capable of harnessing dark and forbidden powers that none of the other Zeti dare to use, and mentally in that he believes that everything is pointless in the cosmic scheme of things, having given up on hope, happiness and life, making him a very depressed individual to the point of nihilism. He is fought as the boss of Silent Forest.
He is voiced by Sam Riegel in English, and Yuki Tai in Japanese.
The Deadly Six made another appearance during the "Zazz Raid" event in Sonic Runners. During the event, Zazz stole Power Rings and consistenly bothered Sonic, Tails and Knuckles in an attempt to get revenge on them after what happened in Sonic Lost World, only to fail every time. He goes to each of the other Zeti for advice on how to beat the heroes, though their advice either doesn't work or the others just tease him. Zavok tells him to keep on fighting, knowing full well that Zazz cannot hope to beat Sonic; however, Zazz's constant failures will allow the Zeti to gather the information they need so that one day, they'll destroy Sonic.
They also appear in Super Smash Bros. for Wii U as a collectable trophy.
The Deadly Six had made an appearance in the Archie comics as part of the Worlds Unite crossover. Originally under Eggman's control, the Zeti were then ordered to help Eggman and Dr. Wily create a new body for Sigma, the antagonist of the Mega Man X series, as well as special armor made for them. Upon completing Sigma's body, the Zeti try to control him, but the Maverick knew they would do this, and used mind-control mechanisms in their armor to fully control them. While under Sigma's control, the Deadly Six split up into two groups and captured Sonic and Mega Man.
In the second act of the crossover, the Unified Army take on the Deadly Six, but the Zeti use their powers to take control of every robot (including the Robot Masters, Maverick Hunters, Gemerl and Bunnie's bionic limbs) and turn them against the rest of the heroes, but are ultimately defeated by the two doctors and removed from the story. Due to Xander Payne resetting everything by changing history, the Deadly Six are sent back to the Lost Hex. Their return was hinted at in a few instances after the conclusion of Worlds Unite.