Why did Godzilla x Kong: The New Empire bring back a seemingly dead titan?

Godzilla x Kong: The New Empire made a giant splash as it hit theaters. Much to the surprise of MonsterVerse fans, the director of the film, Adam Wingard, brought back a seemingly dead character for the finale.

Mothra, like Godzilla, is a kaiju and the only one with any kind of sway over the latter. Therefore, her return in the finale was important, even if it was unanticipated. Moreover, her return highlighted her importance in the MonsterVerse, as stated by the director.
The new MonsterVerse film brings back an important character (Source: Godzilla x Kong: The New Empire)

Godzilla x Kong: The New Empire director opens up about the reason he brought back Mothra

Adam Wingard grew up watching the monster movies from Toho Studios. This includes films that depict the King of the Titans as a godlike figure with friends, such as Mothra or Anguirus. Moreover, some of those features did not shy away from showing the Kaiju as a monster that was born as a result of nuclear radiation.

Mothra was first introduced into the world of titans in the 1964 film, Mothra vs. Godzilla. The titan was first depicted in a mural in Kong: Skull Island in 2017 and then made her official entry into the MonsterVerse in 2019 with Godzilla: King of the Monsters.

The titan’s return was surprising, to say the least, because she fell when taking on Ghidorah in King of Monsters. However, she returned in The New Empire as Godzilla’s and Kong’s ally against Skar King, the most feared villain in the MonsterVerse.
Mothra returns in the finale (Source: Godzilla x Kong: The New Empire)
Wingard spoke extensively about her appearance in his interview with Den of Geek. He emphasized her importance as a titan that the others respect and listen to, including Godzilla.

“She’s a pure vessel within the MonsterVerse and she’s like the great negotiator of the monsters. Everybody respects Mothra. She’s the one monster that all the monsters I think will let do her thing, and it’s the only monster I think that Godzilla truly respects. He respects her opinion. So Mothra says, ‘Listen, we need your help,’ Godzilla’s gonna listen,” he said.

Her return has caused a fair bit of confusion, since Mothra, as we know her, died. However, in King of Monsters, there was another egg, which could be the version seen in The New Empire. The director refused to comment on it but added that, hopefully, future films might give an answer.

Why is Mothra an essential character in the MonsterVerse?

Since the Lepidopteran titan made her entrance in King of Monsters, Mothra has become an essential character in this fantastical world. She has been a loyal ally of Godzilla from the very beginning.

She even helped the King of Titans against Ghidorah, which cost her her life. However, her sacrifice elevated her in the eyes of Godzilla.
Mothra is an important player in the MonsterVerse (Source: Godzilla: The King of Monsters)
Moreover, her return in The New Empire saw her immediately join the fight against the Skar King and Shimo. Most importantly, she influenced the Titans to take on their common enemies instead of battling each other.

The MonsterVerse has managed to bring some of the most iconic Titans alive on screen. Each kaiju has a role to play, and Mothra plays her part faithfully. Hopefully, her story will be explored further in this universe.