Alexander can be a devastating enemy to face when he's initially available. He has high HP and unless one fights him with the Warriors of Darkness, Alexander has no exploitable weakness. Both his offensive and defensive abilities are powerful, as like most bosses, he can attack many times in a turn. His arsenal includes Divine Shot, which hits the party for moderate damage, but since he can use this twice in succession the damage can be significant. He can cast Holy for high damage on a single character, and usually this means he will act once that turn. Alexander's strongest attack is Divine Wrath, which deals massive damage, and is made more dangerous as Alexander will always cast Dispelga on the party nullifying buffs and ensuring great damage.
Alexander's defenses are potent as he can counter physical attacks by casting Protect and cast Shell when a magic attack is used against him. Thus for large portion of the battle Alexander will be buffed while the party is weakened.
Alexander follows a strict pattern of attacking with Divine Shot and occasionally Holy for around two to three turns before using Divine Wrath again.
It is recommended to wait until the Warriors of Darkness and Light are both playable to have an easier time, as attacks such as Ebony Slash from a Dark Knight can deal massive damage to Alexander. The same is true if said party has Diabolos with them. Alexander's attack pattern gives the Warriors of Light time to recast buffs and throw the strongest attacks possible. It is recommended the party has learned Fusion Abilities, such as Hastega and Mighty Wall, as they will provide potent buffs in short time. Mighty Wall is of great help as it increases both defense and offense.
Alexander can be beaten as soon as he's available but it requires a bit of grinding, preferably party level 55, and another White Mages besides Sophia with Doublecast. Sophia will help greatly in the battle by providing healing through Curaga, and she can cast Dispel in response to Alexander's buff if one can afford it instead of healing. The other White Mage can also Dualcast Curaga and buff the party with Haste, Shield and Protect. The other members can focus on damaging Alexander without worrying about their HP.
"Alexander" is a common western name of Greek origin, the original name being Ἀλέξανδρος (Alexandros), "Protector of Mankind". It may also be a reference to the famous Macedonian king, Alexander the Great.