The Mega-Kaiju appeared in the 2018 movie called Pacific Rim Uprising. The Mega-Kaiju is a Kaiju Hybrid created using the forms of Category IV and Category V Kaiju Raijin, Hakuja and Shrikethorn. The Mega-Kaiju is the amalgamation of Raijin, Hakuja, and Shrikethorn merged together by swarms of smaller, robotic hybrid Kaiju. It displays a few attributes of its previous forms and towers over the Jaegers.
The Mega-Kaiju is a hexipedal Kaiju with two tails that have spear-shaped ends, similar to Shrikethorn's, the arm carapace of Hakuja on its two arms and four digitigrade legs, and Shrikethorn's shoulders fused with Raijin's upper arm structure.
Parts of Raijin's head carapace appear below the neck and on the chest, and the head is a fusion of all three Kaiju, with Hakuja's lower jaw separating into two tusks, Raijin's facial structure and Shrikethorn's upper head structure. It has ten eyes, five on each side of its head.
Along its back are several jagged, carapace-based spines, and the Kaiju sports a color scheme similar to its Kaiju components. As a fusion between two Kaiju and Raijin, the Mega-Kaiju is able to use Raijin's ability to redirect kinetic energy.