TMDb/Marvel Studios: Building Celebrity Castle Doom's location, Black Panther 3's mystical turn, & a major VisionQuest cameo. New MCU rumors revealed. April 18, 2026 AceShowbiz - Fans of the Marvel Cinematic Universe are buzzing with fresh rumors about upcoming projects. Recent reports have shed light on the location of the iconic Castle Doom, a critical setting expected to play a significant role in future MCU storylines. Alongside this, there are intriguing hints about the next chapter in the Black Panther saga.