Older sister to Sistermon Blanc and twin to Sistermon Noir, Sistermon Ciel wears a veil shaped like a mouse on its head. Sistermon Ciel acts separately from its sisters Noir and Blanc, wandering the Digital World investigating various disturbances and sending information to Gankoomon about the areas it visits. Though demure by nature, Sistermon Ciel’s resolve is ironclad, and it tends to be popular with local Digimon wherever it goes. By day it goes about what appears to be a peaceful and charming life, and by night it abruptly turns into an assassin dedicated to hunting down any undesirable elements that it has learned about.
It is quite fond of its sword Shirotsume Ichimonji, and its signature move Shirotsume Ichimonji-giri involves silently cutting down foes with the blade. It also knows a variety of assassination techniques, including Byakusai, where it throws a pair of knives hidden up its sleeves at foes, and Piercing Wasp, which involves striking an opponent’s vitals from close range after getting them to let down their guard.