This sexy, sadistic bearer of the white mage's asterisk uses a variety of white magic such as cure, protect, and aero. I wish I could have met her...
Holly mainly uses Protect to help defend Barras and then herself, occasionally attacking. Holly casts Cure on her party, which heals around 70 up to 80 HP. She will usually avoid healing unless one of the two is close to death. She rarely casts Aero.
The player should target Barras first, Defaulting to protect against his powerful attacks and raise BP to launch a counterattack. The player should heal with Treat or Potions as necessary to keep Tiz and Agnès above half health. When their BP is full, the party should launch a full Brave attack against Barras, hopefully defeating him. If not, the party must continue to press the offensive until he falls. Once he does, Holly will not be difficult to defeat.
However, Barras and Holly make a formidable duo. During later fights, Holly uses Aeroga and Cura to heal and support Barras. Barras, on the other hand, has the ability Invigorate, which will either hurt everyone or boost his P.Atk for two turns. Invigorate, if it fails, deals massive damage to friends and foes alike. Bring a White Mage to Dispel any support effects Holly happens to give, and to heal from the Invigorate.