An ancient undead entity, cursed to roam the dimensions for eternity.
These heralds are citizens of a long-lost civilisation that established outposts across many dimensions, roaming to establish their faction's dominance.
An unfortunately too-effective protection magic originally cast over them to protect them from the varied environments has left them unable to rest,
trapped in a never-ending campaign of relevance.

The Undead Herald will trade various banners for coins, with the available stock depending on the dimension they are found in.
The banners themselves serve no purpose, and appear to be purely for decoration.

They don't appear to have any actual use for the coins, with the transaction remaining as a reminder of the herald's original purpose.