After obtaining the Crown, head to the Northwest Castle, located northwest of Cornelia. This castle is home to Astos, the Dark Elf. Present the Crown to him, and he will reveal his true form and attack you. Astos is a powerful magic-user, capable of casting FIR2, ICE2, LIT2, and SLEP. He is a challenging boss for this stage of the game. Focus your strongest physical attacks and offensive spells. Have your White Mage ready with healing spells. Upon defeating Astos, you will receive Matoya's Crystal, which is needed to awaken the Elf Prince. This battle is a significant hurdle.
While the original Astos encounter relies on turn-based spell cycling, Final Fantasy VII Remake reimagines such boss pressure through its dynamic ATB system and real-time elemental weaknesses.
While Astos initiates combat through deception in the Northwest Castle, Final Fantasy X-2 later evolved this antagonist archetype by introducing the more morally complex Shuyin.