As word spread Monday of Justin “Nero” Christian’s death, heartbroken friends mourned the passing of a popular Studio City tattoo artist killed in a freeway collision with a wrong-way driver in Chatsworth the day before.

The 38-year-old man was one one of two men pronounced dead at the scene following the head-on collision early Sunday on the 118 Freeway east of De Soto Avenue. A 25-year-old woman, whom friends described as Christian’s girlfriend, was listed in critical but stable condition Monday, according to a CHP spokesman.

“Nero” was a fitting nickname for this “tattooist extraordinaire” because of his fiery personality and his incredible sense of humor, said close friend Clay Clement, owner of Studio City Tattoo Inc., where Christian worked for about eight years.

“He just burns the place down with his personality,” he said.

Clement also described Christian, who had been living in the San Fernando Valley, as a doting father of a six-year-old girl and “an exceptional human being.”

“He had the uncanny ability to bring attention to the elephant in the room and through humor, make fun of the elephant at the same time,” Clement recalled. “He was a mirror of reality in such a positive way.”

Tricia McCall, another friend, described Christian as “incredibly considerate” and very funny.

“And he would want people to know that he was witty and well-dressed for sure,” an emotional McCall said.

“You have two people in a car…. minding their own business…unexpectedly, here’s a car in front of them, and we won’t even know if there was any time to react.” — Leland Tang, California Highway Patrol

A GoFundMe page set up to help Christian’s daughter had raised more than $7,000 as of Monday evening.

“Justin loved AnaBella with his whole heart and soul, he was an incredible father and would do anything for his little girl,” the page stated. “The two of them were best friends, and this loss is devastating.”

California Highway Patrol investigators are now working to determine why a 30-year-old Los Angeles man identified by coroners officials as James R. Gubera, Jr. drove the wrong way on the 118 Freeway in Chatsworth early Sunday, causing the collision that killed him and Christian.

“We know who entered the freeway the wrong way, so we know who caused the collision,” said CHP Officer Leland Tang, a spokesman. “We just don’t know why…Why did (Gubera) enter the freeway? Where did he enter the freeway? We don’t have answers to those questions.”

The autopsies for both men were still pending as of Monday. Toxicology tests will determine whether alcohol or drugs could have played a role in either driver’s behavior, Tang said. Those reports are not expected for several months, he added.

Tang acknowledged that there are other reasons, besides impairment, that could cause someone to drive the wrong way, including a medical condition.

At 12:24 a.m Sunday, the CHP received a report of a wrong-way driver traveling west on the eastbound 118 Freeway west of the 405 Freeway, the state agency has said in a news release. While responding, they were notified of a collision on the 118 Freeway east of De Soto Avenue.

After arriving, CHP officers determined that a man, later identified as Gubera, was driving a 2014 Toyota in the wrong direction “for unknown reasons” in the carpool lane of the eastbound 118, the agency stated.

Meanwhile, Christian was driving a 2003 Lexus eastbound in the same carpool lane, and crashed head-on with the Toyota.

Both Christian and Gubera were pronounced dead at the scene about 12:45 a.m., according to the CHP. Both were wearing seat belts.

Tang said it was “a miracle” that Christian’s passenger survived the head-on freeway collision — and that no other vehicles were involved.

Part of the investigation will involve creating 24-hour profiles for each of the deceased in an effort to retrace their steps and find out what they did, ate and drank in the hours before the collision, Tang said.

“It’s a very tragic occurrence,” Tang said. “You have two people in a car…. minding their own business…unexpectedly, here’s a car in front of them, and we won’t even know if there was any time to react,” he said.

Sunday’s 118 Freeway collision was the first of two double-fatal, wrong-way crashes reported on Los Angeles County freeways within a matter of minutes during the early-morning hours Sunday.

A woman and a man died, and another woman was seriously injured, when a minivan got onto the southbound 605 Freeway north of Ramona Avenue in Irwindale, heading in the wrong direction, according to the CHP.

The minivan plowed head-on into another car traveling south, in the correct direction, killing both drivers and injuring a female passenger who was riding in the car, according to Officer D. Julien of the CHP’s Baldwin Park office.

The woman at the wheel of the minivan was suspected of driving under the influence of alcohol or drugs, Officer Rodrigo Jimenez added.

Staff writer Brian Day contributed to this report.