So, I've been seeing this question pop up a lot in threads about fantasy finales. People tend to assume the biggest, flashiest magic is always the key. But with a lot of these epic stories, I find the real turning point is never that straightforward. In 'The Dragon's Oath', for instance, the protagonist spends three books mastering draconic incantations, only to have them utterly fail against the Lich King's wards. The spells were a red herring, a test of will. The actual defeat came from a forgotten clause in an ancient pact, something the hero only understood because they'd bothered to learn the language of the runes, not just the fire-breathing words.
The spells were crucial, don't get me wrong. They leveled the playing field, destroyed the phylacteries guarding the throne room, and bought the time needed for the final, subtle move. Thinking they were the 'key' is like saying a battering ram is the key to taking a castle; it gets you through the gate, but the real work happens inside, sword in hand. The author loves subverting the 'chosen one with a superweapon' trope. The dragon magic was never meant to be a win button; it was the journey that taught the mage humility and strategy.