Her name may possibly be derived from the English word “palm”. As a fortune teller, Balm could be described as a "palm reader" even though she uses Tarot cards.
Collect energy from Tarot cards
Balm was a Youma of Jadeite's who enlisted her help upon noticing the energy humans invested in seeking to know their future through clairvoyance. Balm would manipulate her victims by planting a devil tarot card into their victims, which caused them to behave mischievously around people.
One such victim was Umino. Naru recommended that Umino should see a real fortune teller to predict his future. Unfortunately, Umino fell victim to Balm and began to act out of character by attending school without his uniform, eating in front of his teacher Ms. Sakurada, flipping her skirt, distracting her class, pelting rocks at a teacher’s office and demanding a kiss from Usagi.
Other students were taken under Balm's control as well, joining in with Umino as they distracted Ms. Sakurada's class and pelted rocks at a teacher’s classroom. All these victims were the target of Jadeite‘s plan to gather the “rebellious energy of the young”.
Whilst in disguise, Balm attacks Sailor Moon with her tarot cards, which turned into knives when hurled at her. As a Youma, Balm would use her hair as appendages to grab her opponents, as well as use her victims to defend her. Sailor Moon defeated the youma with her Moon Tiara Action attack after being encouraged by Luna and Tuxedo Mask.