The career and character of retired Gen. Jim Mattis has come under a microscope recently, since the revered Marine officer was tapped by President-elect Donald Trump to be the next defense secretary.

The outpouring of reports and recollections published during the past several weeks offers some new insight into how the man known as the "Warrior Monk" might lead the nation's military and shape its national security strategy.

For example, a former Marine officer who worked for Mattis wrote recently about the general's management style. Mattis does not micromanage people – instead, he "fired those who were incapable or lazy, and empowered his staff to make decisions and carry out his intent," according to Joe Plenzler, a retired Marine Corps officer who served as Mattis' public affairs officer.

In Task and Purpose, Plenzler wrote about "15 Things Mattis Taught Me About Real Leadership." 

On the Middle East, Mattis says his biggest concern is Iran. When he was the head of U.S. Central Command from 2010 to 2013, Mattis considered the regime in Tehran to be a bigger long-term threat than the Arab-led militants like al-Qaida and the proto-Islamic State group.

"Nothing, I believe, is as serious in the long term, in terms of its enduring ramifications…as Iran," Mattis said in April, according to this profile of Mattis from longtime defense reporter and author James Kitfield.

Mattis's strong anti-Iranian views were troubling to the Obama White House as well as some senior officers at the Pentagon, who worried those views could fuel a new conflict, according to a profile in Politico.

Yet despite Mattis' blunt talk about killing the enemy, many foreign policy experts say Mattis will be a strong supporter of non-military tools and the civilian-led efforts often referred to as "soft power."

The general once told lawmakers on Capitol Hill: "'If you don't fully fund the State Department, then I need to buy more ammunition."

His nomination was applauded by the U.S. Global Leadership Coalition, an influential group in Washington that lobbies for investing in the civilian size of national security tools, like development and diplomacy.

"He has long been a forward-looking strategic thinker, championing the use of America's civilian tools alongside the military to keep our nation safe, including strong investments in development and diplomacy," said Liz Schrayer, the group's CEO, in a statement in early December.

Some view Mattis' return to public life with concern. The distinctly liberal Nation magazine published a story under the headline " Trump's Cabinet Is a Coup Waiting to Happen," voicing fears about Trump tapping too many retired generals for top civilian jobs.

Yet inside the tightly knit Marine Corps community, Mattis is viewed with unique reverence.

Many Marines say morale soared in units under Mattis's command.

One memorable storyrecounted how Mattis, who has never married nor had children, offered to clock a Christmas Day shift as the "officer of the day" at a command post at Marine Corps Base Quantico.

Mattis was a one-star general at the time, but had offered to sleep on the daybed in the command center on Christmas so the younger officer assigned to that shift could spend the holiday with his family.