Balm was a Youma summoned by Jadeite to drain energy from humans as part of the Dark Kingdom's continuing energy-gathering efforts. She posed as a fortune teller in the House of Fortunes in anime episode 2. There, in human guise, she used her powers to drain energy from humans and put them under her control using special cursed cards. The carrier of a card would do whatever they desired without inhibitions, as Balm had commanded, leading them to be rude and even violent. Gurio Umino was one of those who fell under her spell, after consulting Balm on what to do about his crush on Usagi.
When Sailor Moon arrived at the House of Fortunes to see what was going on, Balm instructed the boys to attack her after Balm used her tarot cards as throwing blades. The boys managed to corner Sailor Moon as Balm transformed into her true self, a hideous woman with a mess of black hair that could be used as a weapon. At that point, Tuxedo Mask arrived and threw a rose at Balm’s face, distracting her and stopping the hypnotized boys in their tracks. Sailor Moon then had to dodge Balm as the Youma attacked Sailor Moon with her hair, forming it into two hands that clawed viciously after her opponent. After dodging the claws, Sailor Moon then used Moon Tiara Action, destroying Balm and releasing the boys from her spell. http://www.wikimoon.org/index.php?title=Balm