Nizar Rayyan, the senior Hamas leader killed in an Israeli air strike, was a vitriolic cleric who had called for suicide attacks on Israel.
Nizar Rayyan was said to be one of the top five Hamas leaders
The day before a missile flattened his apartment in Gaza, he appeared on Hamas-run al-Aqsa television promising to hit Israel "even deeper" than before.
"God willing, the evil state, the Jewish state will not break the resistance," he said.
If Israel embarked on a ground operation, Hamas could "kill the enemy and take hostages", he warned.
Media reports described Mr Rayyan as one of Hamas's top five decision-makers; the liaison between the Hamas leadership and the group's military wing.
A bearded man in his late 40s, he lived in the Jabaliya area of northern Gaza and was described as both preacher and university lecturer.
He was seen as one of the group's most hard-line leaders, sometimes wearing combat fatigues and a cartridge belt to patrol the streets with Hamas fighters.
He was fundamentally opposed to the state of Israel.
"We will never recognise Israel," he told Reuters news agency in early 2007. "There is nothing called Israel, neither in reality nor in the imagination."
Nizar Rayyan was seen as close to the military wing of Hamas
In October 2001, one of his sons launched a suicide attack on a Jewish settlement in Gaza. Two Israelis were killed and 15 injured.
When Hamas seized control of Gaza in June 2007, he said there would be no dialogue with Fatah, the secular Palestinian movement it ousted, "only the sword and the rifle".
Months later, he told a rally in Gaza City that Hamas would soon control West Bank areas administered by Fatah.
Unlike some Hamas leaders, he opted to remain in his home when the Israeli air bombardment of Gaza began in late December, Hamas radio said.
The Israeli government said his house was serving as a weapons store and Hamas communications centre.
Mr Rayyan, two of his four wives and a number of his children were killed when the Israeli missile struck, Palestinian officials said.