Jettis were, and are, very real. It’s been a while since I read Cornwell’s Sharpe series, so I can’t vouch for everything he says about them, but they certainly existed in the period he describes, and still do.

Jettis are first mentioned in the Hindu epic Mahabharata around the 9th century BC, where they are said to have fought alongside Lord Krishna (i.e., on the side of the Pandavas). There is no evidence that Jettis in more recent times are connected to the Jettis of the Mahabharata. Their history in recent times is confined to the region of Karnataka, specifically the kingdom of Mysore, whereas the incidents of the Mahabharata take place in north India. The Jettis themselves have the tradition that in the distant past they migrated south from their original homeland in Baroda, which may be true.

Jettis are an ethnic group among Hindus, about evenly divided between Vaishnavs and Shaivs (worshippers of Vishnu and Shiva, respectively), but they also have their own special deity Nimbajdevi, with a bunch of temples dedicated to her scattered across the south (in Dhenuvadi, Tirupati, etc.). They have a unique ceremony they call “matti puja” or earth worship which they perform in their gyms. Other than that, they are pretty typical Hindus.

They have their own form of martial arts, which combines unarmed combat (a mix of wrestling and boxing) with armed combat chiefly involving a kind of knuckleduster with spikes that’s used for punching and slashing. Here’s an example from the late 19th century from the Pitt Rivers Museum. It was traditionally made of either buffalo horn or steel. It’s a very old form of combat, going back over 2,000 years, but these days it’s very highly stylized, meant for exhibitions rather than actual fighting. The biggest annual exhibition matches are on the Hindu festival of Dushehra, which is the 10th day (Vijaydashmi) of the festival of Navaratri (the 9 nights). This is particularly big in the state of Karnataka, where it’s their state festival, and the Jettis still perform exhibition matches on Dushehra in Mysore.

These matches are a very old custom and were originally sponsored by various kings and princes in the region. There are lots of descriptions of them from the British who wrote about them when they first arrived. Here’s a description written by a guy called Rice in the Mysore and Coorg Gazetteer from the early 19th century:

Mysore, I believe, is the only country in the south of India in which the institution of Jettis has been preserved on its more perfect forms than those which are exhibited at these interesting but cruel sports. The combatants clad in a single garment of light orange coloured drawers extending half-way down the thigh, have their right arm furnished with a weapon which for want of a more appropriate term, we shall name a caestus, although different from the Roman instruments of that name. It is composed of a buffalo horn, fitted to the hand, and pointed with four knobs, resembling very sharp knuckles, corresponding to their situation, with a fifth of greater prominence at the end, nearest the little finger, and at right angles with the other four. This instrument properly placed would enable any man of ordinary strength to cleave open the head of his adversary at a blow.

He goes on to describe it as a very bloody “sport”, with the combatants severely injured before the king calls a halt to the fights.

Another account comes from James Scurry, who was taken prisoner by Tipu Sultan in one of the Anglo-Mysore wars of the late 18th century:

The Jettis would be sent for, who always approached with their masters at their head, and after prostration and making their grand salams, they would be paired one school against another. They had on their right hands the wood guammootie (vajramushti) of four steel talons, which were fixed to each back joint of their fingers, and had a terrific appearance when their fists were closed. On being matched and the signal given from Tipu, they began the combat, always by throwing the flowers which they wear around their necks in each other’s faces; watching the opportunity of striking with the right hand on which they wore this mischievous weapon which never failed lacerating the flesh and drawing the blood most copiously.[ … ] They were obliged to fight as long as Tipu pleased, unless completely crippled, and if they behaved well, they were generally rewarded with a turban and a shawl, the quality being accorded to merit. [ … ] Another sort of combat, much more terrible than already mentioned and which is nowadays only seen at Baroda is the Nackika-kushti, that is to say, fight with claws. Here the combatants are almost naked, but adorned with crowns and garlands, tear at each other with claws of horn. These claws were formerly of steel and caused certain death but they have been abolished as too barbarous for modern times. Those now in use, as I have said, are of horn, and are fixed to the closed fist with thongs. I was only once present at a combat of this kind, for my heart was so moved by the horrible spectacle that I refused to go again. [ … ] The arena is covered with blood; the defeated combatant is carried off; and the conqueror, the skin of his forehead hanging down in stripes, prostrates himself before the king, who places round his neck a necklace of fine pearls and covers him with garments of great value.

Aside from the exhibition and “sports” aspects, Jettis served other roles. While they occasionally fought in the king’s armed forces, they were more often part of the king’s bodyguard than regular military. They were also the king’s personal executioners. Many of the British accounts mention that their typical method of execution was to grab the prisoner’s head and snap his neck with a quick jerk. The Brits are equally horrified at how easily they did it, and appreciative that it was relatively quick and painless. I believe Cornwell mentions this in some of his Sharpe books too.

Here are a couple photographs of Jetti exhibition matches from the late 19th century, recorded by the Brits: 1, 2, 3.

A good book to read about this stuff is L. K. A. Iyer’s The Mysore: Tribes and Castes.

Yes, they were, and apparently they do still exist.

Jetti is a corruption of the Indian name Jyesthimalla, which translates to 'excellent fighter/wrestler', roughly. Joseph Alter wrote a book called The Wrestler's Body, which concentrates on North Indian ideas of identity as they're expressed through physical activity. You can read it online, too