His creations are integral to the success of the Marvel Cinematic Universe (MCU), which has reinvented the category of superhero films.

As comic book fans and film buffs all over the world mourn the loss of a comic book pioneer, here are eight things you might not know about Lee.

1. He will feature in upcoming Marvel films

For fans of the MCU, Lee's cameos in the films are highlights to look out for.

Those concerned that they have seen the last of him on the big screen do not have to worry, though, as Avengers co-director Joe Russo has confirmed that his cameo for Avengers 4 has already been filmed.

The scene was shot alongside Lee's cameos for Avengers: Infinity War and Ant-Man And The Wasp.

It is also rumored that Lee will make appearances in two other MCU films, Captain Marvel and Spider-Man: Far From Home, which will be released in March and July 2019.

However, he is not in the next installment of the X-Men franchise Dark Phoenix, Entertainment Weekly reported.

2. He started out writing obituaries

Before joining Marvel Comics, then known as Timely Comics, as a 17-year-old, Lee worked a host of odd jobs.

He was a theater usher, delivered sandwiches and was an office assistant at a trousers manufacturer before he got his first writing job.

However, he found his gig to be a depressing affair as he often had to prepare these obituaries in advance so that newspapers could rush them to print when the person died.

Thanks to his uncle, he got a job at Timely Comics as an errand boy and later went on to writing and editing duties.

His first contribution to the Marvel comic universe? Captain America Foils The Traitor's Revenge, published in May 1941.

3. He chose a pseudonym for his comics career

Although he became an assistant at Timely Comics at a young age, comic book writing was never his long-term plan. Instead, he had harbored dreams of becoming a novelist.

Reserving his birth name, Stanley Martin Leiber, for his "serious" writing career, the Spider-Man co-creator split his first name into "Stan Lee", thinking that he would pursue his dreams when he had the time.

However, he never went down the novelist path as his slate of comic book creations left him with no time to spare.

4. He served in the US military

Lee made his name creating superhero characters that resonated with the public, but few know that the comic book creator was a military veteran himself.

He served in the US Army Signal Corps during World War II from 1942 to 1945, enlisting shortly after hearing about the attack on Pearl Harbor.

In 2017, he was inducted into the Signal Corps Regimental Association, which he called one of his "proudest achievements".

Read also: Stan Lee, creator of Spider-Man and other Marvel superheroes, dead at 95

5. He did not intend for Iron Man to be well-liked

"Genius, billionaire, playboy, philanthropist."

Robert Downey Jr's iconic line as Tony Stark/Iron Man in the MCU underscores his fan-favorite status, but the character's popularity was not anticipated by Lee.

"I thought it would be fun to take the kind of character that nobody would like, none of our readers would like, and shove him down their throats and make them like him," Lee said in a 2008 interview for the first Iron Man film.

"And he became very popular."

Iron Man was created at the height of the Cold War, making his first appearance in Marvel comic anthology series Tales Of Suspense in March 1963. The first Iron Man title was published in May 1968.

6. He nearly quit writing comics in the 1950s

Frustrated by his publisher's request to "dumb down" his writing in the 1950s, Lee wanted to leave the comic book business.

His last project would have been The Fantastic Four, which debuted in 1961, a new superhero team created in response to the popularity of DC's updated Flash and Justice League of America super-team.

In contrast to his publisher's brief, Lee eschewed mindless action in favor of complex dialogue. The Fantastic Four was a huge success and changed his stance on leaving the comics industry.

7. He collaborated with Dr. Seuss

After his stint with the army's Signal Corps, Lee worked as a playwright in the Training Film Division.

While writing training films, he worked with several writers who received critical success later in their careers. They included Pulitzer Prize winner William Saroyan, The Addams Family creator Charles Addams and Theodor Geisel, better known as Dr Seuss.

8. He banned the use of exclamation marks

Temporarily, at least.

At one point in 1971, Lee felt that Marvel's traditional use of exclamation marks was childish and banned them.

The idea was implemented after the issues had been prepared for printing and the exclamation marks were just erased entirely.

For three months, Fantastic Four and Amazing Spider-Man, which Lee was working on, had weird punctuation marks. Other writers at the time ignored his ban.

When he stopped writing the two titles, the incoming writers reinstated the exclamation marks and Lee did not enforce the ban either.