The Royal Bunker was a secret underground bunker built to shelter the Inhuman Royal Family in case of emergency. Due to the destruction of Attilan, rebel Prince Maximus was trapped and abandoned in it.
The Royal Bunker was a secret facility built for the Inhuman Royal Family. However, not all members of the Royal Family knew about it. King Black Bolt and his brother Maximus were among the ones to be aware of its existence.
When the Inhuman Royal Family returned to Attilan after days of exile due to Maximus' rebellion against them, Black Bolt instructed the teleporting dog Lockjaw to take them inside the Royal Bunker. Upon discovering this secret location, Queen Medusa was upset that her husband had kept the existence of the Royal Bunker a secret from her.
Hidden in the Royal Bunker, the Inhuman Royal Family devised their plan to retake Attilan from Maximus' grip. While the rest of the Royal Family remained in the Bunker, Triton left to sabotage the installations throughout the city. Meanwhile, Karnak asked Evan Declan, who they had brought along with them, to explain what Maximus had asked him to do. Thus, Karnak learned about Maximus' plan to undergo a second Terrigenesis.
Following the failed parley with Maximus, the Inhuman Royal Family returned to the Royal Bunker. Black Bolt and Medusa discussed their relationship before they were interrupted by Karnak, who requested the authorization to put the deceased Gorgon through a second Terrigenesis to revive him. Although Black Bolt and Medusa refused, Karnak left the Royal Bunker to carry on his plan all the same.
Later, Medusa went to see her sister Crystal, who was alone in the Royal Bunker and cried because of having left Dave, her human friend who she had fallen in love with. After they discussed the matter, Medusa comforted her sister.
Eventually, Triton caused sufficient trouble in the city, which enabled him to capture Maximus, who was taken prisoner in the Royal Bunker. Maximus was interrogated by the Royal Family and revealed that he had enacted a fail safe which could trigger the destruction of Attilan.
Therefore, Black Bolt told Medusa and Crystal to prepare for the evacuation of the city while he and Triton took Maximus to force him to stop the impending collapse of Attilan. They failed to do so as Maximus managed to escape, prompting Black Bolt to return to the Bunker with Karkak and a revived Gorgon. They reunited with Medusa, who informed them that they were ready for evacuation.
Before they confirmed the need to leave the city, Medusa requested one last attempt to negociate with Maximus. She left the Bunker for the throne room, but failed to convince Maximus. She returned to the Bunker and informed her family that they could not stop Maximus, forcing them to leave Attilan.
Before they left, however, Black Bolt decided to punish Maximus. He let the rest of the Royal Family leave Attilan and went to recapture his brother. Black Bolt brought Maximus back to the Royal Bunker. Black Bolt pushed his brother inside the Bunker and abandoned him in the building, breaking the door so that Maximus could not escape. At first, Maximus screamed and begged to be released, but eventually figured out that no one would come and accepted his fate, left to be the King of an empty kingdom.
- "Enough food and water to last eternity. Built to withstand an attack from whom? Let's hope I never have to find out."
The Royal Bunker was an extremely resistant underground facility designed to provide shelter to the Inhuman Royal Family in case of emergency. As such, it provided all the equipment and supplies necessary to live in it for a long period of time, albeit in basic conditions. The shelves contained years worth of food and the refugees were provided somewhat basic bunks to sleep in. The Bunker also featured an armory so that the refugees could defend themselves.