Zerase never joined the the Prince's quest because she thought it was noble, and she never felt much kinship with the other peons she served with. This turns out to be a good thing in this matchup as she will have no compunctions about unleashing the power of the Star Rune and frying Belcoot on the spot. While Belcoot's Falcon attack may prove frightening, it only matters if he lives to bring it to bear against Zerase. Since Zerase is faster and Belcoot's magic defense is sorely lacking, that won't happen. Zerase will feel absolutely horrible about having to kill the boy though. No, really.