An Ominous Banner is a special, uncraftable banner that can only be obtained from raid captains or found at pillager outposts. It is distinct from regular banners due to its unique pattern—composed of eight layers, making it impossible to craft or copy in a loom. In Java Edition, the banner uses a white base with several layered patterns including cyan lozenge, black fess, and light gray roundel, among others. In Bedrock Edition, it exists as a separate banner type that also cannot be used in looms.

Ominous banners are most commonly dropped by raid captains such as pillagers, vindicators, or evokers carrying them. These mobs always drop the banner upon death, and the banner itself can be broken quickly with or without tools—though axes are fastest. If the block the banner is attached to is removed or altered, the banner also breaks and drops.

In Java Edition, the Ominous Banner can be equipped as a helmet via commands, which is how raid captains wear them. In Bedrock Edition, they appear in the chestplate slot using NBT editors. They cannot be worn or equipped in Survival mode. While they serve the same function as regular banners when placed in the world, they have some unique properties. They can be used as map markers in Java Edition, used as fuel in furnaces (smelting 1.5 items per banner), and placed under note blocks to produce bass sounds.

Although they can be applied to shields in both editions, only six of their patterns transfer, and the original banner is consumed in the process. The shield's durability or enchantments remain unaffected. Because of their complexity, ominous banners cannot be duplicated with looms like normal banners. Additionally, in Java Edition, players can rename ominous banners using an anvil or commands, and the custom name persists even after the banner is placed and retrieved.

Overall, the Ominous Banner is a trophy-like item that marks a player’s encounter with a raid captain, and serves as a functional decoration with a striking and rare design.