Complex sentence: They used numerous spells including beckoning spells, location spells, and fire spells as weapons, and used their black breath to cast curses, which caused dark depression among their foes, causing them to freeze in terror.
Split into simpler sentences: They used numerous spells including beckoning spells, location spells, and fire spells as weapons. They also used their black breath to cast curses, which caused dark depression among their foes, causing them to freeze in terror.