Rum is the living doll assigned to Shirley as her face. She's extremely shy and speaks very little, always worried about saying something wrong or upsetting people around her. That said, Emilico's infectious enthusiasm eventually starts to loosen her up a bit.
Unlike most living doll and shadow master pairs, Rum and Shirley don't share as strong a bond. But Rum has her own way of coping: she's got an imaginary friend named Rummy who lives in her left index finger, marked by a black ribbon (which matches Shirley's white one). When she needs to talk things through, you'll catch her bending that finger slightly as she "converses" with her invisible companion.
Rum's got an impressive photographic memory, something that comes in handy during the Debut arc when it becomes clear just how sharp her recall actually is.
Content compiled by AnimeList.moe from publicly available sources.
