The awful thing about wickedness is just how interesting it is. Kind and benevolent rulers; admirable warrior kings; even the fumbling but kindly nice ones who build hospitals and live blameless lives – they all pale into guilt-wrenching insignificance when set before a list saturated by the sinful, iniquitous, and depraved.

And in this respect, Sri Lanka is spoilt for choice, simply by virtue of its statistics.

Around 200 kings, with the odd queen, ruled the island from its first recorded beginnings in 543 BCE to its last king, who was packed off into exile by the invading British in 1815. From island-wide kingdoms to ones circumscribed by covetous foreign occupiers, the 2358 years of royal rule the country enjoyed were a considerably different experience. It was just as Longfellow had once said of a little girl: “When she was good, she was very, very good/ But when she was bad, she was horrid.”

The country’s monarchs averaged little over 11 years a reign, but with massive variances. Most lapped up a rule of just a few years; sometimes, only a few hours.

A happy few enjoyed reigns that must have seemed an eternity to their fortitudinous subjects. But if the ancient chronicles are to be believed, almost half of them died well ahead of their divinely allocated time – at the hands of their own successors, often sons, sometimes brothers, uncles or even wives or occasionally an invading Indian emperor or edgy Tamil warlord.

No studies have been conducted to precisely identify which country can claim to be the most regicidal. Still, in any future list, only a fool would put money on Sri Lanka not scoring somewhere around the top 5.

From this long, bloody start, regicide took a modest back seat during the rule of the Dutch and the British. But things picked up after independence in 1948. Assassination, often but not always fostered by civil war, promoted the killing of a sitting president, a prime minister, and a leading presidential candidate, Vijaya Kumaratunga, whilst another almost killed his own wife, the then president, Chandrika Kumaratunga, in 1999.

It was but one of many other fortunately failed attempts at regicide that the independent republic had to face, a trait that reduced, at times, its own leaders to accusing one another of hatching yet more malodorously mortal plots.

But selecting just 6 of the country’s most egregious baddies – barely 7% of the total of potential scoundrels - is as tricky as deciding which chocolate to take from an Anton Berg’s Heart Box. The box has an impossibly delicious mix of pralines, marzipan, nougat, soft caramel, coconut, sea salt, orange, Chocolate Liqueur, Nut Truffle, hazelnut, cherry, and apricot. To make it to this list, a Sri Lankan monarch had to be very bad indeed, a real and indisputable villein.

The list begins, quite neatly, with the county’s first recorded king. Embodying a prescient creation myth, which, like many of their type, mixes horror and achievement in equal measure, as with going into labour, Prince Vijaya fits the bill perfectly.

As Romulus and Remus had earlier demonstrated in faraway Rome, being a founding father often necessitated random acts of abomination and cruelty. And so it was with Prince Vijaya. Even his father heartily disapproved of him.

Coming from a royal Indian family said to have been descended from lions, psychologists might argue that the prince never had a chance. Violence was in his nature.

But the Mahavamsa, the great ancient Chronicle of Sri Lanka that is rarely modest in praising anything remotely proto nationalistic, pulls no punches when it comes to its paterfamilias. Given its mission (“compiled for the serene joy and emotion of the pious,”) the Mahavamsa had little other choice but to call a spade a spade.

“Vijaya,” it begins, as it meant to go on, “was of evil conduct and his followers were even (like himself), and they did many intolerable deeds of violence. Angered by this, the people brought the matter to the king; the king, speaking persuasively to them, severely blamed his son. But all fell out again as before, the second and yet the third time; and the angered people said to the king: `Kill thy son.’”

For the king, this helpful request enabled him to kill two birds with a single stone. He chose to rid himself of not just his own son, but of most of his kingdom’s rogues, whilst demonstrating, like the consummate politician he was, blameless clemency. The Mahavaṃsa records how “then did the king cause Vijaya and his followers, seven hundred men, to be shaven over half the head and put them on a ship and sent them forth upon the sea, and their wives and children also.”

The problem was exported. The prince sailed away from India and “landed in Lanka, in the region called Tambapanni on the day that the Tathagata lay down between the two twinlike sala-trees to pass into nibbana.”

This time, reference (“Tathagata”) to Lord Buddha notwithstanding, the renegade prince wasted little time in smiting most of those whom he first came across. His ruthlessness and expedient mindset can be seen at work in his marriage to Kuveni, a tribal princess, who was herself no stranger to brutality.

Piecing together what actually happened on his arrival is all but impossible. Still, from the extravagantly violent tales told in the Mahavamsa, the vagabond prince likely found no empty island – but rather one already well stocked with people who had ordered themselves in tribes, perhaps even miniature kingdoms. To carve out his own domain necessitated fighting, and in this, a marital alliance with a local princess who could help him in the fight was invaluable.

In piecing together the ghostly DNA of Sri Lanka’s pre-Vijayan native kingdoms, historians have had to turn to local folklore, Indian epic poems like the Ramayana, and the Mahavaṃsa itself. Still, the picture they present is blurred and fantastical.

There was the Ramayana, a half-human tribe founded by the ten-headed demon King Ravana, whose followers have gone down in history as a terrifying lot given to cannibalism.

A further tribe, the serpent-like Naga, may exist only in myth, despite references to Lord Buddha arriving among them to settle disputes. The Nittaewo, dark skinned, tiny, and understandably defensive, are a possible third tribal strand, their last members possibly smoked to death.

On marginally surer ground are the Yaksha, described by the Dipavaṃsa, the oldest of the island’s three ancient chronicles and which, with support from the later Mahavaṃsa, could have given rise to the Vedda.

Archaeogeneticists believe the Vedda are descendants of the original Mesolithic settlers who migrated from India 40,000 years ago. Scattered communities still exist today, an ever more ghostly presence on the island, their bloodlines dissipated by intermarriage.

They worship a range of ancient folk deities, as well as mainstream Hindu gods such as Murugan. Ancestor worship and the cult of the dead mark out many of their still-living practices.

This was Kuveni’s tribe, and they seemed to live in scattered communities of kingdoms in various parts of the island. Overcoming her first instinct to kill him, Kuveni instead married him, and on their wedding day, she helped hatch a plot to kill her own clansmen.

They married in a wave of blood. If this was a most Lady Macbeth-like way to ensure freedom and foreclose on reprisals, it was no less monstrous of Viyaja, who more than fulfilled his homicidal role in eliminating all nearby native chieftains.

The Mahavaṃsa describes how “he listened to her and did even (as she said) he...