Last week IS fanatics made a chilling threat against Prince George. Photo / Getty Images
The Islamic State doesn't tend to discriminate when it comes to who is killed in attacks plotted by the terror group - but it still has its prime targets.
Isis, one of the world's deadliest and most active terrorist organisations, has long promoted and supported attacks in Australia and other countries and conducted daily attacks on security forces and civilians in Iraq and Syria.
While its goal is to inflict maximum bloodshed, it also has targets on the backs of individuals including NASA and FBI staffers as well as Australian university lecturers, Defence officials and public servants, hit lists released by the terror group in recent years have showed.
But at the top of the group's hit list for trophy kills are high profile individuals whose brutal murders would be considered by Isis as the ultimate mark of notoriety and revenge against the West.
It was this week revealed that Isis fanatics made a chilling threat against Prince George saying: "Even the royal family will not be left alone."
The barbarous extremists allegedly posted a picture of the future king on encrypted instant messaging app Telegram with the horrifying message.
A picture of the young royal outside his $34,000-a-year school in Battersea, South London, was also reportedly shared on the app along with the school's address and the comment "school starts early".
The message allegedly also included words from a jihadi song which translated as, "When war comes with the melody of bullets, we descend on disbelief, desiring retaliation". Security expert Greg Barton told news.com.au the threat was likely nothing more than a bid for attention by Isis.
"They want attention and notoriety so they aspire to attack symbolic targets," he said. "It's aspirational.
"It doesn't make any practical sense because it's so hard to do ... there would be no one harder to get than a member of the royal family because of their personal security."
Mr Barton said Isis was well versed on how to spin propaganda.
"They've made audacious claims about locations and the expansion of their fight but picking prominent celebrities in this fashion is something new," he said.
"Their core group is very good at understanding how propaganda works but it's not clear if this is coming from the long tail or amateurish fan boys."
Mr Barton said the latest threat against Prince George had probably prompted the royal family's security teams to "look again at any weaknesses" but that it was unlikely it had been considered credible.
But the four-year-old prince is not the only prominent world figure the terror group has its sights set on.
US President Donald Trump
Earlier this year, Isis drew up a hit list of more than 8700 people urging their followers to "kill them wherever you find them".
The pro-Isis United Cyber Caliphate (UCC) hacking group has released a video message threatening the United States, President Trump, Britons and thousands of others.
"We have a message to the people of the US and most importantly, your President Trump," the chilling message read.
"Know that we continue to wage war against you. Know that your counter attacks only make us stronger. The UCC will start a new step in this war against you. So expect us soon Insha Allah!
"We will release as list with over 8000 names, addresses and email addresses of those who fight against us. Kill them wherever you find them."
The British Royal Family
Prince George isn't the first - and most likely won't be the last - British royal to be threatened by Isis.
Just last month, a disturbing extremist video challenged Prince Harry to fight jihadis.
In the English-language clip a man, identified as Abu Uqayl, said: "Why don't you come here and fight us if you're man enough, so that we can send you and your Apaches to hellfire?"
Isis last year published a hit list targeting high profile Muslims including Hillary Clinton's long-time aide Huma Abedin.
The list of moderate Muslim targets was published in the terrorist group's glossy propaganda magazine Dabiq - which is aimed at recruiting jihadists from the West.
Abedin, who has been Clinton's top aide since the mid-1990s, was named as a "politically active apostate" alongside US Rep. for Minnesota, Keith Ellison, and British Members of Parliament, Baroness Sayeeda Warsi and Sajid Javid.
Pope Francis
US President Donald Trump last year described Pope Francis as "Isis' ultimate trophy".
"If and when the Vatican is attacked by Isis, which as everyone knows is Isis' ultimate trophy, I can promise you that the Pope would have only wished and prayed that Donald Trump would have been President," Mr Trump said during the presidential campaign.
His comments came after the Pope said a man who thinks about building walls and not bridges was "not Christian," a sharp reprimand for Mr Trump's vow to build a wall along the US border with Mexico.
In 2014, Isis militants called for war against the Catholic Church in the latest issue of the group's English-language propaganda magazine Dabiq. The extremists Photoshopped Isis' signature black flag over an image of the Vatican's iconic Egyptian obelisk with a cover headline that read: "The Failed Crusade." The "crusade" was reportedly a reference to air strikes led by the US and other countries