That was not intended to be taken seriously (limericks aren't). Just that my muse delivers things in that format, by choice, and has to be cajoled into producing sonorous declamations.
A mark of fire, five points enflame,
Drink down the blood, the flesh devour,
The sacrifice at full moon claim,
When third and fifth conjunct, in power.
And if, by dawn, the deed's not done,
Unstoppable new rule shall greet the sun.
"Ugh!" said Seona "That's gross. You wouldn't really drink someone's blood, would you?"
"And you're the one who's been complaining about the price of meat in the market. I'm not even certain I would want that much power, but that "unstoppable rule" worries me. It might be benevolent but, historically, rulers with no checks and balances tend to become despots, if well-meaning despots. How long can an empowered live?"
"As long as he wants to, more or less. Easy enough to prevent ageing if you've enough power on hand."
"I suppose the first people to see are the astrologers. Haman, you would be good for that."
"Why would we need an astrologer? We've already got a prophecy, and I doubt whether they could narrow it down much. They specialise in imprecision."
"For that 'conjunct'. What apart from planets have 'conjunctions?"
"Grammarians?" Taya's ironic voice cut through. "Although I doubt if it were one of them, or it would be 'conjoin'."
"Now this 'mark' of 'five points enflamed'. Though it might be 'five points in flame'; the original words would have been spoken, and only written down afterward. He might have stuck his hand in a fire and burnt all the fingertips to uselessness. That sort of thing frequently triggers the use of power."
"There's a merchant shipper who brands his cases with a symbol of three flames." Seona was starting to get into the game. "Check whether there's anyone who uses five – a cadet branch, maybe. Getting branded would certainly be an experience that 'marked' you. But why are you saying 'he' all the time?"
"The 'ruler'? No, that could be a she, or even an it."
"A 'she' would make looking for the enflamed points more fun." Haman ducked as Taya launched a playful punch "But how could it be an 'it'? 'It's can't rule."
"And you a cat person. But it's not certain that the power source will be the 'unstoppably ruler'. Just likely. So we can't -um 'rule out' any life form with flesh. I admit straight away that a nice beef steak sounds much more appealing than 'baby tartar'."