Carmilla

Carmilla is the Witch of Lust (also known as the Witch Factor of Lust) in Re:Zero − Starting Life in Another World. She is one of the seven Witches of Sin from over 400 years before the main story.

She appears as a timid, fragile-looking young woman with long light pink hair, red/yellow eyes (depending on the source), and an adorably meek and uncommonly cute rather than strikingly beautiful appearance. She typically acts extremely shy and low in self-confidence, often stuttering, speaking politely, avoiding conflict, and behaving in a very hesitant, downcast manner.

Her Authority of Lust allows her to captivate and entrance anyone who sees her, making them so absorbed in gazing at her that they lose awareness of everything else — often to a deadly degree, where their heart can stop without them even noticing. Ironically, this power caused massive unintended chaos in her lifetime (wars, rebellions, destruction) as people projected idealized versions onto her and fought over her, despite her never wanting any of it.

She was ultimately burned at the stake but her soul was preserved (by Echidna) and she appears in the series during events in Arc 4 (in the Sanctuary's trials), where she has a supporting role. Despite her gentle demeanor, she's considered one of the more quietly terrifying witches due to her passive yet overwhelmingly dangerous ability and hidden capacity for deep grudges.