Oh, shut up and help me remodel the Astaroth (The After Years) page!
Cecil, Rydia, Rosa, Kain, Edge, or Yang, Golbez, Ceodore, Ursula, and Leonora should be around levels 60 or 40. Compared to the other bosses on this floor, Astaroth is pretty easy. If you have a party member that knows reflect, or even better, two, reflect all party members instantly. Astaroth's main threat is her magic, which can easily be reflected back to her. She also has a physical attack which drains your HP and heals hers, however it's not that strong and shouldn't prove to be a problem. She uses Firaga, Blizzaga, Thundaga, Death, Flare and Embrace, all of which can be reflected. As long as you don't run out of MP and can keep casting Reflect on party members, this fight should be a breeze. While your mages cast Reflect it might also be useful to note that she does not counterattack, so you can attack with your warriors to whittle her HP down faster.
- Oddly enough, in Final Fantasy IV The Complete Collection, Astaroth's sprite is that of Lucifer, or its Soul of Rebirth sprite, instead of her original sprite from the original game.