Ogryns are dumbasses. Unfortunately they're such dumbasses that sometimes they don't even know they're fighting for the wrong team. This is where Chaos Ogryns or Ogryn Brutes comes in. Chaos renegades are quick to forcibly conscript them into their ranks and doing so is pretty damned easy. They just tell the Ogryns that the new Gods they are fighting for is instead another variation of the Emprah. To make them more lethal, the renegades use crude surgical procedures, combat drugs, and sorcerous rituals to control the beasts and set them upon their enemies. Modified and warped by forbidden methods, the Ogryn Brutes can be split into two varieties, these include Ogryn Berserkers and Plague Ogryns.
Ogryn Berserkers are Ogryns corrupted by Khornate Chaos Warbands, driven insane by bloodlust and evolving into ferocious and bloodthirsty beasts. Similar to Khorne Berzerkers, these creatures were lobotomized and injected with a powerful combat drug known as "Slaught". Once Slaught is introduced into the bloodstream, the Ogryn becomes a raging psychopath. The downside of this treatment is the drug-fueled rampage cannot be sustained by the Ogryn's body and complete organ failure is an inevitable result of prolonged combat by Ogryn Berserkers.
Ogryn Berserkers are known to be surgically modified by their masters in order to create a more potent killing machine. These include surgically removing limbs and replacing them with blades, buzz-saws, or other vicious weaponry.
Plague Ogryns are Ogryns warped by the powers of the Chaos God Nurgle, and have become bloated and putrid harbingers of disease. Similar to Plague Marines, they are utilized by Nurgle warbands. The members of this species have been greatly mutated by the forces of the Chaos god Nurgle who have turned these Abhumans into large masses of diseased bloated beings. The hardy and strong Ogryn had proven to be an ideal breeding ground for nightmarish plagues that have turned them into twisted hulking creatures. The mutations inflicted on them have made the Plague Ogryns almost impossible to kill, and the slightest touch from them can bring about a horrible death on their enemies. Their creation first came on Vraks at the hands of the Traitor Chaos Space Marines warband known as The Tainted. These devoted disciples of Nurgle were responsible for using their sorcerous arts to transform the labour Ogryn forces on Vraks that were part of the rebel forces that turned against the Imperium.
Since that time, the savants of the Ordo Malleus have come to believe that the secrets of creating Plague Ogryns have been further refined by the Tainted from within their home in the Eye of Terror. As a result, they have traded these festering creatures to other devotees of Nurgle in return for new subjects with which they can continue to practice their craft.
Ogryn Brutes, whether vanilla, Khorne or Nurgle affiliated, are tough motherfuckers. They are essentially Chaos Spawn on steroids-OHGODNOOOOOOOOOAFBKDNOANJDJALIJDOASASDAARRRGHHH!....continuing on from my predecessor, each Brute is Fearless, with Hammer of Wrath and Rampage, which means with their base D6 attacks, you could potentially have 11 attacks per model on the charge. One brute can be upgraded to a Packmaster, which loses Rampage, but allows you to take up to 6 Chaos Hounds, which has some impressive combat stats (WS3 S5 T5 W2 I4 A3), and they allow you to roll 2D6 picking the highest for Sweeping Advance. They can be dedicated to chaos gods for about the price of a typical power fist, giving them either 2D6 picking the highest for their attacks (Khorne), Feel No Pain (5+, Nurgle), Fleet (Slaanesh), or an additional close combat weapon with Soul Blaze (Tzeentch). Additionally for a flat rate, you can give the squad Flak or Carapace armour, which means with Nurgle, they could be quite tough to kill. Overall, while a squad of 5 Nurgle Brutes with Carapace armour is looking at a whopping 360 points, but they’re likely to wreck anything they make it into combat with.