Marvel Studios' extensive cast announcements for *Avengers: Doomsday*, beginning with the 2025 livestream reveal and continuing through D23 and SDCC footage, have established a sprawling ensemble drawing from MCU veterans like Steve Rogers and Thor, the Fantastic Four, Fox-era X-Men, Thunderbolts, and Wakandan/Talokan characters. Official listings confirm roughly 30–36 appearances, with Robert Downey Jr.'s Doctor Doom as the central antagonist driving multiversal conflict. Directors have teased additional unannounced roles, while recent *VisionQuest* post-credits scenes and promotional materials fuel speculation around figures like the Hulk or Vision. With the December 18 theatrical release imminent, the next trailer or final marketing push could resolve lingering questions on borderline cases before resolution.