SINGAPORE - With the release of Thor: Love And Thunder, a record has been reached: The superhero, as played by Chris Hemsworth, is the first Marvel Cinematic Universe (MCU) character to get four solo movies.

In Hollywood, a mix of business and personal decisions determines a character's longevity. Captain America's Chris Evans, for example, chose to leave the MCU to work in theatre and other films.

Hemsworth, who has played Thor in eight films (four solos and four as part of the Avengers team), and Mr Kevin Feige, president of Marvel Studios, drill into the reasons the Norse god has stuck around for so long.

The two, along with Hemsworth's co-stars Natalie Portman, Christian Bale and Tessa Thompson, were speaking to the media last week at an online global press conference.

Australian actor Hemsworth, 38, says in the third solo movie, Thor: Ragnarok (2017), the hammer-wielding hero got a much-needed injection of goofiness.

In Ragnarok, New Zealand director Taika Waititi made Thor Odinson the god more like Hemsworth the person. "He brought out the immature, young, adolescent quality that I embody. It was exciting and new and fresh. It's something Thor didn't have in the original films," says Hemsworth.

The first two films, Thor (2011) and Thor: The Dark World (2013), took deep dives into comic-book Norse lore. The hero was an angsty prince embroiled in the politics and wars of his empire.

Mr Feige, 49, who also serves as producer, says the reborn Thor in Ragnarok happened after his team saw that Marvel heroes with solo movies tend to have human and mostly American origins. They include Peter Parker (Spider-Man), Dr Stephen Strange (Dr Strange) and Carol Danvers (Captain Marvel).

Unlike them, Thor was born a deity.

"For so long, we said, 'Well, he's a Norse god. How do we make him relatable?' And we spent so much time making sure that audiences connected with him. But they are so with him now that, yes, we could go on towards a part four," says Mr Feige.

Thor's relatability makeover included making Asgard, Thor's realm, a place filled with vulnerable families. The god was also surrounded by comic-relief types, such as the large, sweet-natured warrior Korg (voiced by Waititi), the drunk mercenary Valkyrie (Thompson) and a confused Hulk (Mark Ruffalo).

In the new film, Gorr (Bale), a being who hates all gods, threatens the stability of the universe because he has found a way to murder them. Thor, now fit again after the events of Avengers: Endgame (2019), finds allies to counter Gorr. His companions include Valkyrie, Korg and former lover Jane Foster (Portman), now gifted with superpowers and given the name Mighty Thor.

American actress Portman, 41, plays Foster, the scientist introduced in the first Thor movie as a love interest. In the new film, they are estranged. But that is not the only thing that has changed: Portman's buff body has generated some online interest in her gym routine.

"I was grateful that they cast a five-three actress in a six-foot role," she says, referring to Foster's height as depicted in the Mighty Thor comic books. When she pauses in her reply to a question about her bodybuilding regimen, Hemsworth jumps in, remarking that Portman "led the charge" when it came to weightlifting.

Another actor whose body went through a transformation - though one that was less obvious than Portman's - is Bale. The English actor's sickly horror-film look was devised so that he was the "polar opposite" of the happy, healthy Thor.

"Gorr is someone not relatable, a bit of a loner, creepy, someone no one wants to be around," says Bale, 48, adding that while he might be "a monster, a butcher", the audience will discover that his lust for god-killing did not come from nowhere. "There's a possibility of understanding why he came to be that way."

Gorr's greyish flesh tone stands in contrast to the rest of the film's neon colour scheme. The look of the film, including the jagged font used in its poster, reflects director Waititi's schoolboy passions. He wanted a look that summed up his teenage obsession with hard rock in general and bands such as Guns N' Roses and Metallica in particular.

The 46-year-old says: "I wanted it to be bombastic, loud and colourful, to reflect the spray-painted panel vans of the 1980s and rock album covers. The title treatment is the kind of thing I would've drawn in my books in class when I wasn't listening - I remember spending months and months perfecting the Metallica logo at school.

"To reflect that in this crazy adventure we're presenting is a dream come true."

Thor: Love And Thunder opens in cinemas on July 7.