“I think at his core, KSM is rotten. There’s something really, really wrong,” says Terry McDermott, co-author of The Hunt for KSM.

The book, recently released, tracks Mohammed’s path from his youth in Kuwait through North Carolina Agricultural and Technical State University in Greensboro to Bin Laden in Afghanistan. It concludes all the harsh interrogation techniques got the United States no closer to finding bin Laden. A differing account, just written by the ex-CIA official who oversaw the secret interrogations, Jose Rodriguez, argues the techniques were crucial to national security.

But on Mohammed’s ambition the men agree. “As near as we can tell, from 1992 until he was captured, he did nothing but terrorism,” McDermott said. “In that time he probably came up with 100 different ideas for how to kill people. It was nonstop.”

Now, he faces off with the new chief judge of military commissions, Army Col. James L. Pohl, as the lead defendant in the complex conspiracy prosecution that Attorney General Eric Holder wanted put before a civilian jury in Manhattan — “in a courtroom just blocks away from where the Twin Towers once stood.”

Congress thwarted that ambition. So now, all five men will be brought before Pohl at Guantánamo’s maximum-security court complex in a rare Saturday arraignment that starts the so-called speedy time clock toward trial before a military jury of 12 or more field-grade officers, called a Military Commission. Attendance at the arraignment is mandatory, to hear the charges against them and answer the judge on whether they’ll accept their Pentagon-paid defense teams.

They are:

Walid bin Attash, 33, a Yemeni who lost his leg in a 1997 battlefield accident in Afghanistan, sits behind Mohammed in court and is cast in the charge sheets as the No. 2 of the so-called “Planes Operation.”

He’s a former al-Qaida training camp instructor who allegedly handpicked some of the Sept. 11 hijackers out of a hand-to-hand combat training course two years before 9/11 — and brought them to Mohammed in Pakistan. There they practiced on a computer-driven flight simulation program and learned the English they needed for their mission.

  Ramzi bin al Shibh, 40, sits behind bin Attash in court. Bin al Shibh is another Yemeni who is described in the charge sheets as applying four times to get a U.S. visa, starting more than year before the terror attacks, and failing each time before ultimately serving as a Hamburg, Germany, based deputy, transferring funds to some of the hijackers as well as trying to enroll himself along with the actual hijackers in Florida flight schools.

In 2009 at Guantánamo, before the Bush-era trial was abandoned, bin al Shibh was never able to persuade the court that, like Mohammed and bin Attash, he was competent enough to function as his own lawyer in court. Instead, he was prone to outbursts — from interrupting proceedings to offer Muslim holiday greetings to bin Laden to observing that then-judge Ralph Kohlmann, a Marine colonel, had a Jewish-sounding name.

He was the first of the five to be captured, according to news reports, in a Pakistani-U.S. intelligence raid a year to the day after the 9/11 attacks, on Sept. 11, 2002, in Karachi, Pakistan.

•   The computer engineer who introduced himself in court as Ammar al Baluchi, 34, is identified as Ali Abdul Aziz Ali in court documents. A nephew of Mohammed, he’s a Pakistani by nationality who speaks excellent English and is accused of moving money and making travel arrangements for the hijackers. His charge sheet describes him as a would-be martyr who, just weeks before Sept. 11, sought a one-week visa to visit the United States on Sept. 4. He was turned down, and seized by Pakistani authorities on April 29, 2003, in Karachi along with bin Attash.

  Mustafa al Hawsawi, 43, a Saudi national, also is accused of moving money and credit cards to some of the hijackers, helping some buy clothing while in transit from Dubai, the United Arab Emirates, to Orlando, via London. At one point he sent a package to one of the United Airlines hijackers in Delray Beach. CIA agents captured him on the same day as Mohammed on March 1, 2003, in Rawalpindi, Pakistan, according to leaked documents. Like the other alleged 9/11 conspirators, he disappeared into the agency’s secret prison network, only to surface at Guantánamo in September 2006, a transfer Bush announced in a White House press conference.