YAHYA Sinwar, named leader of Hamas on Tuesday, masterminded the bloodiest attack on Jews in a single day since the Holocaust, having made no secret of his desire to strike hard at Israel, the country that imprisoned him for almost half his adult life.
In December 2022, the militant leader told a rally in Gaza that the Palestinian group Hamas would deploy a "flood" of fighters and rockets against Israel, in a speech to supporters that bore the hallmarks of crowd-pleasing hyperbole.
"We will come to you, God willing, in a roaring flood. We will come to you with endless rockets, we will come to you in a limitless flood of soldiers, we will come to you with millions of our people, like the repeating tide," he said in his address.
Less than a year later, Israel discovered it was no idle threat, when Hamas fighters broke through Gaza's fence on Oct. 7, 2023, staging an assault that killed 1,200 people, took 152 hostage and broke Israel's reputation as an invincible enemy.
Sinwar, 61, who before Tuesday's announcement was the Hamas chief in Gaza, began his career as a ruthless enforcer who punished and killed collaborators with Israel, before rising to a leadership role after his release from prison in 2011 and his return to Gaza.
The war set off by the Oct. 7 attack laid waste to Gaza, as Israel sought to eliminate Hamas. Sinwar has been at the top of Israel's assassination list during the conflict.
By the time of the speech, Sinwar and the militant Islamists' military leader Mohammed Deif had already hatched secret plans for the Oct. 7 assault, the deadliest day in Israel's 75-year history.
Hamas regarded the attack as a major victory against Israeli occupation, but it drew condemnation from the International Criminal Court.
Its prosecutor said he had requested arrest warrants for Sinwar, Deif and another Hamas figure over the attack, and for Israeli Prime Minister Benjamin Nentanyahu and his defence chief over Israel's response which reduced much of Gaza to rubble.
Both Israel and Hamas dismissed the accusations and said they objected to the way the announcement of the request on the same day appeared to equate them with each other - though they faced different charges.
Heard in hindsight, Sinwar's words foreshadowed what was to come, an attack Hamas dubbed the "flood of Al-Aqsa," a reference to the mosque in Jerusalem that is one of Islam's holiest shrines and stands on a place revered by Jews as Temple Mount. Al-Aqsa has been subject to repeated Israeli raids.
Sinwar never made a public appearance after the Oct. 7 attacks, but directed military operations along with Deif and another commander. He also led negotiations for prisoner-hostage swaps, possibly from bunkers beneath Gaza.
In the days after the Oct. 7 attacks, Sinwar was seen by some of the captured Israelis in the tunnels, freed hostages have said. Hamas and Israeli officials did not publicly comment on the reported sighting.
The question of hostages and prisoner swaps is deeply personal for Sinwar, who spent 23 years behind bars, and has vowed to free all Palestinian prisoners held in Israel.
He was one of 1,027 Palestinians released from Israeli prisons in a swap for a single Israeli soldier held in Gaza in 2011.
Born in the Khan Younis refugee camp, Sinwar was elected as Hamas' leader in Gaza in 2017. After Oct. 7, Israel's Defence Minister Yoav Gallant said he and other leaders were "living on borrowed time."
Before he was jailed, Sinwar rose to prominence as the head of the Al-Majd security apparatus which tracked and killed Palestinians accused of providing information on Hamas to Israel's secret service.
Both Hamas leaders and Israeli officials who know Sinwar agree he is devoted to the movement to an extraordinary level.
One Hamas figure based in Lebanon described him as "puritanical ... with an amazing ability of endurance."
Michael Koubi, a former Shin Bet official who interrogated Sinwar for 180 hours in prison, said he clearly stood out for his ability to intimidate and command.
Koubi once asked the militant, then aged 28 or 29, why he was not already married.
"He told me Hamas is my wife, Hamas is my child. Hamas for me is everything."
Sinwar was arrested in 1988 and sentenced to consecutive life terms accused of planning the abduction and murder of two Israeli soldiers and the murder of four Palestinians.
In jail, his hard line against collaborators continued, Israelis who dealt with him have said.
At times, "he did not have Jewish blood on his hands, he had Palestinian blood on his hands," Yuval Bitton, previously head of the Israel Prison Service's intelligence division, told Channel 12 TV in October.
Bitton, a dentist who treated Sinwar, said Israeli medics removed a tumour in Sinwar's brain in 2004.
"We saved his life and this is his thanks," said Bitton, referring to Oct. 7. Bitton's nephew was killed during the attack and his body taken to Gaza by the militants.
Koubi described Sinwar as being devoted to the destruction of Israel and to killing Jews.
The senior Israeli officia added that "I don't think the way he grasps reality is similar to more rational and pragmatic terrorists".
Bitton added that the Hamas leader was willing to allow huge suffering for a cause and had once in prison led 1,600 prisoners to the brink of a mass hunger strike until death if needed in protest at the treatment of two men in isolation.
"He was ready to pay any price for the principle," he said.
* The writer is from Reuters