Rosalind "Rose" Marroweater is a thin and wiry halfling who first appeared in Marielda during "The Killing of the King-God Samothes By The Traitor Prince Maelgwyn Pt. 3" as one of the High Sun Day guests. In Winter in Hieron it is revealed that she presided over the halfling "deal" with the gnolls that stole their land and history, and so Rosemerrow is named after her.
In "The Meeting House", the Mountain Party first see her depicted on the doors of the Rosemerrow Meeting House wearing a crown of thorns. They encounter and fight with her shade in the strange grey lamina connected to the Meeting House, along with other ancient halflings. There, she is carrying a green spear and wearing ceremonial armor. Like the other shade halflings, she first appears grey-skinned and white-haired. She is apparently venomous.
In the aftermath of the events of "The Killing of the King-God... Pt. 4", she stole the Sword of Samothes from his forge. At some point, the sword was separated into blade and hilt. The light of the blade shows the grey version of the halflings, while other lights make them look as they did when they were alive; "neither of those is wrong, neither of those is a weird illusion."