By playing this card while you already have a "Magical Citadel of Endymion" with 3 Spell Counters on it, you can nuke your opponent's field immediately after "Flame Lord"'s summon.
This card works well in Spellcaster decks in general, as many common staples of Spellcaster decks can contribute to "Flame Lord"'s summon. For example, "Legendary Flame Lord" can be summoned in a "Dark Magician" deck using "Advanced Ritual Art". Also, in Spell Counter Decks, "Toon Table of Contents" (customarily used in 3s) can immediately build up the necessary 3 Spell Counters.
Ritual summon this card with "Djinn Releaser of Rituals" to restrict your opponent's summoning options after "Flame Lord" nukes the board. Your opponent will be limited to their one normal summon each turn, which can easily be removed by another burst of this card's effect.