Summary

• The Kaiju attacks are part of an invasion plan orchestrated by extradimensional beings who aim to consume different worlds for colonization.
• Jaegers require two pilots because the neural load is too much for a single pilot to handle.
• Raleigh and Gipsy Danger had to destroy the breach instead of Stacker because the original plan went wrong and the breach would only allow Kaiju to through.

In the end of Pacific Rim, Raleigh Becket, Mako Mori, and Gipsy Danger cancel the apocalypse by sealing the breach so no more Kaiju can come through, but what did the Kaiju want and how did they figure out how to stop them? Pacific Rim is a 2013 movie directed by Guillermo del Toro from a screenplay written by del Toro and Travis Beacham featuring performances from Charlie Hunnam, Idris Elba, Charlie Day, Ron Pearlman, Rinko Kikuchi, and more.

After the Kaiju began coming through a rift in the Pacific Ocean, the world banded together to create the Jaeger Program, building giant robots to fight back against the monsters. Despite some success with the Jaegers, the program is being shut down in favor of a border wall, but an uptick in Kaiju attacks proves the wall won't work. Bringing back retired Jaeger pilot Raleigh Becket, Stacker Pentecost (Idris Elba) hopes to give the Jaeger program one last shot. The Kaiju attacks are getting bigger, so Stacker Pentecost launches a plan to finally seal off the breach for good to stop the Kaiju forever.

Where Did the Kaiju Come From? What Do They Want?

The Kaiju were sent from another dimension to clear the way for extradimensional colonizers.

Initially it seems like the Kaiju attacks are random, but the steady uptick in attack frequency and Kaiju size begins to look like something a bit more sophisticated than simple monsters coming to take over the world. After Dr. Gottlieb (Burn Gorman) and Dr. Geiszler (Charlie Day) drift with a Kaiju they discover it's all part of a massive invasion plan orchestrated by extra-dimensional beings that's been going on for centuries. Geizler says these other beings are "colonists" who consume world after world. The dinosaurs were their "trial run," but the Earth wasn't ready, so they'd simply been waiting for the atmosphere to change enough to launch their full-scale attack.

Once Raleigh takes Gipsy Danger through the breech, the full scale of the attack being planned by these beings is briefly glimpsed with many more Kaiju laying in wait. According to Geiszler, the category I through IV Kaiju were "nothing," and merely the first wave. He says the next wave they had planned would be the "exterminators" designed to "finish the job" before the "new tenants will take possession." In the breech, these creatures appear more bug-like and monstrous, only a little bigger than humans. It's not clear how dangerous they are on their own, but when the Kaju do their dirty work, they're more than capable of planetary destruction.

Why a Jaeger Requires Two Pilots to "Drift"

The neural load of the Kaiju hunter is too much for a single pilot.

Due to the massive "neural load" required, Jaegers require two pilots, neural linked across the "drift" to operate the right hemisphere and left hemisphere of the brain. Additionally, only certain pilots were "drift compatible" with each other, due to different experiences, personalities, and temperaments, meaning a successful pairing between pilots is essential to piloting a Jaeger, which was incredibly rare. This is why Raleigh and his brother Yancy piloted Gipsy Danger together and why Herc and Chuck Hansen piloted Striker Eureka together and what makes the bond between Raleigh and Mako Mori (Rinko Kikuchi) so special.

Stacker Pentecost and Raleigh Becket are also the only two rangers to ever pilot a Jaeger solo. Putting the entire neural load on a single person is a huge strain, so, in addition to the fact that Mark I Jaegers had poor radiation shielding, the fact that Pentecost spent three hours solo piloting in the Battle of Tokyo put him at risk of death if he piloted a Jaeger again. Stacker and Raleigh's ability to solo pilot could also play a role in why they're able to drift with more than one person, although Stacker also says he "carries nothing into the drift," which enables him to link with Chuck Hansen to pilot Strike Eureka into the final battle over the breach.

Why Raleigh and Gipsy Danger Had to Destroy the Breach Instead of Stacker

Everything goes wrong in the final battle.

The original plan for the final battle was for Stacker Pentecost and Chuck Hansen to pilot Strike Eureka to the breech and drop a nuclear bomb into the hole while Gipsy Danger provided , but everything went wrong and the final victory looked very different. First of all, while only two Category IV Kaiju had come through the breach initially, after the Jaeger's arrived, a third Kaiju, a Category V, came through the breach, making the battle the first-ever triple event and the first-ever appearance of a Category V Kaiju.

Charlie Hunnam had a scheduling conflict with Pacific Rim sequel, Pacific Rim: Uprising, so he was written out of the story by having Raleigh Becket retire as a Jaeger pilot after the events of Pacific Rim.

Second, Strike Eureka sustains damage during the battle that jams the payload delivery system, meaning the Jaeger can't deliver the bomb anyway. Third, when Strike Eureka gets the upper hand on the Category IV Kaiju, it calls in backup, blocking Strike Eureka for the brach, so Stacker decides to sacrificially detonate the payload so Raleigh and Mako self-destruct Gipsy Danger's nuclear reactor instead. Fourth, after Dr. Gottlieb and Dr. Geiszler drift with the Kaiju, they learn the breach will block anything it doesn't detect as a Kaiju, meaning Pentecost and Hansen can't just have Strike Eureka drop the bomb into the drift as planned.

At the end of Pacific Rim, after Gipsy Danger enters the breach, riding a Kaju carcass for access, the Jaeger's reactor overload requires a manual activation, meaning Raleigh can't eject until after he triggers the the overload himself. He successfully jettisons Mako, but has to wait until the last second for his own ejection, when he's already critically low on oxygen. Fortunately, he's able to jettison in time to make it out of the breach before Gipsy Danger explodes and seals the portal.