The War of Kings is the culmination of years of Marvel cosmic storytelling. The Inhumans, led by Black Bolt, have taken control of the Kree Empire. The Shi'ar Empire, under the rule of the mutant Vulcan (Gabriel Summers, Cyclops's long-lost brother), is expanding aggressively. The collision of these two cosmic empires draws in the Guardians of the Galaxy, the Nova Corps and X-Men-adjacent characters across the Marvel cosmic universe.