Miri Yobami belongs to the Hundred Devouring Families’ Yobami lineage, renowned for its mastery of medicine and poisons alongside the Inbami family. Originally born into the Inbami clan, she was adopted by the Yobami, rendering Miyo Inbami her blood sister. Separated in childhood when both were designated as heirs to fortify their families’ standing within the Momobami clan, the sisters devised an intricate sign language to communicate covertly during strictly regulated family gatherings. Petite in stature, Miri sports dark blue hair coiled into twin odango buns, her hollow dark blue eyes framed by crimson shadow. Clad in Hyakkaou Private Academy’s standard uniform, she carries herself with restrained severity. Emotionally detached and taciturn, she channels her focus into meticulous strategy, yet harbors fierce loyalty to Miyo, readily sacrificing herself under pressure to ensure her sister’s survival. In the presidential election, Miri and Miyo conspire to overthrow Kirari Momobami. They poison Yuriko Nishinotouin to amass votes before confronting Yumeko Jabami and Ryota Suzui in Nim Type Zero. Leveraging their secret sign language to share card details, Miri feigns indifference to the lethal stakes of poison needles and antidote wagers. When Mary Saotome and Ryota unravel their tactics, Miyo commands Miri to inject herself with poison, resulting in her elimination. Miyo’s intervention spares her life, and Miri witnesses the election’s conclusion, recognizing their miscalculation of Rei Batsubami’s impact. Miri’s bond with Miyo intertwines profound interdependence with hierarchical strain. Though Miri voluntarily risks herself for Miyo’s ambitions, Miyo manipulates this devotion, directing her to forfeit gambles strategically. Post-election, Miri abandons gambling yet vigilantly monitors Miyo’s safety during subsequent trials, including Miyo’s clash with Mary Saotome in the Grand Tournament. Their dynamic epitomizes the collision of sisterly allegiance and the cutthroat calculus nurtured by their upbringing, encapsulating themes of loyalty, tactical cunning, and the corrosive weight of familial duty amid the Momobami power wars.