You can only activate "Curse of Royal" as a chain to a Spell or Trap Card that would destroy 1 (and ONLY 1) Spell or Trap Card.
You can use Curse of Royal against cards like "Magic Jammer", "Seven Tools of the Bandit", "Solemn Judgment", "Curse of Royal", "Mystical Space Typhoon", "Dust Tornado", "Magic Drain", "Riryoku Field", "Judgment of Anubis", etc.
You cannot use "Curse of Royal" against "Heavy Storm" or "Harpie’s Feather Duster".