All roads lead to Rudy.

Rudy Giuliani, the former New York City mayor who is now President Donald Trump's personal lawyer, is in the news constantly for his role in the impeachment inquiry. But while Giuliani's efforts to have Ukraine launch investigations politically beneficial to Trump are much discussed, it's not the only way he and his associates have woven themselves into the fabric of Trump's world.

Asked in a text Wednesday by NBC News about how his circle has been able to be so influential in the Trump administration, Giuliani responded, "I don't know."

Here's a look at Giuliani's key players and how they intersect with Trump:

UKRAINE

Giuliani's ties to Ukraine go back to at least 2008 when he did consulting work for Vitaly Klitschko, a former boxer who is now mayor of Kyiv. While he's had other business dealings there over the years, Giuliani said he started focusing on Ukraine's alleged role in the 2016 U.S. presidential election as a way of countering special counsel Robert Mueller's probe into Russian election interference.

This year, Giuliani seized on unfounded allegations that Ukraine had scuttled an investigation into Hunter Biden at the behest of his father, then-Vice President Joe Biden, a leading 2020 Democratic presidential rival. Giuliani said his investigative efforts had the president's blessing, which has been confirmed by multiple witnesses in the impeachment inquiry.

But Giuliani had some help with his efforts.

LEV PARNAS and IGOR FRUMAN

Parnas, a Trump donor, told the New Yorker earlier this year that he became "good friends" with Giuliani after the 2016 election. The friendship was lucrative for Giuliani, who told Reuters that Parnas' company Fraud Guarantee paid his consulting company Giuliani Partners $500,000 for business and legal advice last year.

Ukrainian-American businessman Lev Parnas exits following his arraignment at the United States Courthouse in New York on, Oct. 23, 2019. Shannon Stapleton / Reuters file

Parnas, who was born in Ukraine, told the New Yorker he volunteered to help Giuliani's efforts there. "Because of my Ukrainian background and my contacts there, I became like Rudy's assistant, his investigator," he told the magazine.

Parnas and Fruman, his business partner in another company called Global Energy Producers, had already been agitating against U.S. Ambassador to Ukraine Marie Yovanovitch. Federal prosecutors said they raised money for a congressman in 2018, later identified to NBC News as former Rep. Pete Sessions, R-Texas, in order to push for his help in getting rid of the ambassador.

Igor Fruman exits federal court after an arraignment hearing in New York on Oct. 23, 2019. Stephanie Keith / Getty Images file

As NBC News reported in October, the plot against Yovanovitch was driven by Ukraine's former chief prosecutor, Yuriy Lutsenko, who claimed without evidence that the ambassador had given him a "do not prosecute" list. Parnas and Fruman helped Lutsenko connect with Giuliani, and the two discussed a possible investigation into Joe and Hunter Biden. Lutsenko later said that he didn't think Hunter Biden did anything wrong.

Parnas and Fruman also helped connect Giuliani with Lutsenko's predecessor, Viktor Shokin, who claims he was fired for investigating Burisma, the Ukrainian energy company where Hunter Biden worked. There's never been any evidence of wrongdoing by either Biden, but that hasn't stopped Trump and his allies from pushing this narrative.

In addition to their work for Giuliani, Parnas and Fruman had another side gig — doing work for two of Giuliani's longtime friends.

JOE diGENOVA and VICTORIA TOENSING

DiGenova is a longtime friend of Giuliani's who was the U.S. attorney for Washington, D.C., while Giuliani was the U.S. attorney for the Southern District of New York. DiGenova and his attorney wife, Victoria Toensing, have their own Washington-based law firm, diGenova & Toensing, and are fixtures on Fox News, where they've been staunch defenders of the president.

Victoria Toensing and Joseph diGenova listen to former CIA agent Valerie Plame Wilson testify before the House Oversight and Government Reform Committee on Capitol Hill Friday, March 16, 2007. The Washington Post / via Getty Images file

Trump announced they were joining his legal team in March of last year, but had to pull back the offer because of conflicts of interest involving the Mueller probe. "However, those conflicts do not prevent them from assisting the president in other legal matters," Trump lawyer Jay Sekulow said at the time.

As the New York Times and Washington Post reported on Wednesday that the couple, along with Giuliani Partners, had been in negotiations to represent Lutsenko earlier this year.

The husband and wife also worked with a Ukrainian oligarch, Dmytro Firtash, who has been fighting extradition to the U.S. Firtash told The New York Times he'd hired the couple in June at the urging of Parnas and Fruman. Toensing has said she hired Parnas as "a translator" to do work on Firtash's case.

TURKEY

Giuliani has strong ties to the Turkish government and represented a Turkish-Iranian banker, Reza Zarrab, who was jailed in March 2016 on money laundering charges. Zarrab, who had an office in Trump Tower Istanbul, was close friends with Turkish President Recep Tayyip Erdogan and had politically damaging information involving a government-run Turkish bank, Halkbank.

In February 2017, Giuliani met with Erdogan in Turkey about the case, and he later met with Trump and then-Secretary of State Rex Tillerson about Zarrab as well. He had company at both meetings.

MICHAEL MUKASEY

Mukasey, a former prosecutor in the Southern District of New York, worked with Giuliani at a New York City law firm, and the pair remained close over the years even after Mukasey became then-President George W. Bush's attorney general.

Former U.S. Attorney General Michael Mukasey. Yuri Gripas / Reuters file

Mukasey teamed with Giuliani on the Zarrab case, but their addition to Zarrab's legal team did not sit well with New York prosecutors or the judge presiding over the case. The judge, Richard Berman, accused the men of having conflicts of interest — Mukasey's law firm had represented eight of the banks that were victimized by Zarrab, as had Giuliani's firm. Giuliani's law firm had also served as an "agent" of Turkey, Berman found — but he allowed them to stay on the case because Zarrab had "voluntarily and knowingly" waived the issue.

How far they went to do so became clear recently. While NBC News first reported Mukasey and Giuliani's meeting with Erdogan in 2017, the Washington Post last month reported that Mukasey and Giuliani had also met with Trump in the Oval Office about Zarrab that same year. Trump called Tillerson in to meet with them as well. "The president says, 'Guys, give Rex your pitch,'" a source familiar with the meeting told the paper.

They suggested swapping Zarrab for an American pastor who was in Turkish custody. Tillerson considered the request inappropriate, and later complained to Trump's chief of staff, John Kelly, who told him to ignore it, the Post reported.

Zarrab wound up pleading guilty and giving testimony in a related case that was devastating to Erdogan and Halkbank. Federal prosecutors in New York charged Halkbank last month in a multibillion-dollar scheme to violate U.S. sanctions on Iran, and Zarrab is expected to be the star witness at trial.

NAVY SEAL CASE

Two other Giuliani associates have been center stage in a case involving Eddie Gallagher, a Navy SEAL acquitted of murder in the death of a wounded ISIS prisoner.

His cause had been championed by Fox News personalities and was taken up by another Giuliani friend.

BERNIE KERIK

Kerik, an Army veteran, is a former New York City police officer who once worked on Giuliani's security detail when he was mayor. Giuliani gave Kerik the top job in the city jail system, and in 2000 named him police commissioner. The pair worked side-by-side on the day of the Sept. 11, 2001, terror attacks.

Washington Post Live editor Lois Romano interviews Bernard B. Kerik Founder, ACCJR.org at an event on Feb. 10, 2016 in Washington, DC. Kate Patterson / The Washington Post via Getty Images file

In 2010, Kerik would be sentenced to four years in prison for offenses including failure to pay taxes and lying to the White House during his scuttled nomination to be Homeland Security chief.

Since his release, he's become an advocate for prison reform. Like diGenova and Toensing, he's also a frequent presence and Trump advocate on Fox News.

Kerik started acting as an adviser in the Gallagher case earlier this year. He helped set up a legal team that included Timothy Parlatore, who's worked for Kerik in the past, and another Giuliani friend: Marc Mukasey.

MARC MUKASEY

Mukasey, the son of Michael Mukasey, is a former federal prosecutor who worked with Giuliani at two law firms. Mukasey left the firm Greenberg Traurig earlier this year to start his own firm and quickly landed high-powered clients, representing members of the Trump family and the Trump Foundation in a civil case that had been brought by the New York State Attorney General's office. That case officially settled in early November.

Marc Mukasey, defense lawyer for Navy Special Operations Chief Edward Gallagher, arrives to military court on Naval Base San Diego on July 2, 2019, in San Diego. Julie Watson / AP file

Kerik, Parlatore and Mukasey scored a huge victory over the summer when Gallagher was acquitted of the most serious charges against him. Gallagher was convicted of posing for a picture with the corpse, and the court ordered him to be dropped in rank from chief to petty officer first class. The legal team vowed to fight the rank reduction, too.

Trump became a vocal advocate for Gallagher, both restoring his rank and ordering the Pentagon to drop a planned disciplinary hearing against him that could have resulted in his expulsion from the elite unit.

Kerik celebrated the developments with a picture of him, Mukasey and Gallagher. His "prayers have been answered," Kerik wrote.

US Navy Special Warfare Chief Eddie Gallagher, his attorney @MarcMukasey and I having dinner last night in NYC, where he talked about looking forward to his retirement. Thanks to @realDonaldTrump and DOD Secretary @EsperDoD, his prayers have been answered. #GodSpeed Chief! pic.twitter.com/4tREXOK1aJ — Bernard B. Kerik (@BernardKerik) November 24, 2019

Giuliani weighed in on Twitter as well, saying Trump's actions in the case "shows his courage and integrity."

"Not many Presidents would put their neck out on the line," Giuliani said. "It shows how much he values those who protect us!"