At 0:47, this trailer shows what appears to be giant legs emerging from an oil-drilling site. While we don't see the creature itself, as surely Dougherty & Co. want to keep some surprises for the actual film, they would appear to spider-legs, which point to the giant spider-kaiju Kumonga, who debuted in 1967's Son of Godzilla.
In Toho lore, Kumonga hibernated under Sogell Island in a deep cave, and emerged when the ecosystem was threatened by man. Kumonga has been an ally of Godzilla, even after coming into conflict with him, and realized Ghidorah was the larger threat. It's likely the drilling won't be the signal for Kumonga to come to the surface, but instead the other Titan activity occurring across the globe.
At 0:58, there's what seems to be an entire mountain being uprooted, hinting at Anguirus, the irradiated dinosaur who was more of a friend to Godzilla than a creature that merely fought alongside him for survival. While it's an educated guess here, what suggests Anguirus is the shape of the mountain. He debuted in 1955's Godzilla Raids Again, and is known as Godzilla's first rival.
This Titan's Toho appearance was that of a mean four-legged turtle, with spikes on its back and tail, which is the perfect base for a mountain to be perched upon. If any creature were designed to be hibernating beneath a mountain, given its shape it would be Anguirus. If this is indeed the case, then Godzilla would have one more ally in his corner for the war to come.
Last, but not least, there's the star of the show, Godzilla. He looks meaner and far more agile than he was in Gareth Edward's 2014 movie. Maybe it's because in that film he had just woken up and was a bit slow, but as we see him barreling into Ghidorah at the end of this new footage, he's faster than when we last saw him.
It definitely looks as if Godzilla will need some help against Ghidorah, but then again, we don't see him using his atomic breath yet. He just wouldn't be called king if he didn't have a few tricks up his sleeve. Once more, he will be humanity's savior, taking them on as pets and ensuring the balance of the world is kept intact.
Directed by Michael Dougherty, Godzilla: King of the Monsters stars Vera Farmiga, Ken Watanabe, Sally Hawkins, Kyle Chandler, Millie Bobby Brown, Bradley Whitford, Thomas Middleditch, Charles Dance, O’Shea Jackson Jr., Aisha Hinds, and Zhang Ziyi. The film opens May 31, 2019.