Battle Objective: Defeat Velius.
This is a multi-stage boss battle. Velius is a Lucavi demon with high HP and powerful area-of-effect attacks. He is accompanied by several Archaic Demons. Focus your initial attacks on the Archaic Demons to reduce incoming damage. Velius is weak to Holy-elemental attacks, so if you have a Holy Knight or a character with Holy spells, they will be very effective. Keep your party spread out to minimize damage from Velius's area attacks. Use 'Shell' and 'Protect' to buff your units. This battle requires sustained damage and careful healing.